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The application of vernacular Australian environmental design principles in Glenn Murcutt’s architecture

The application of vernacular Australian environmental design principles in Glenn Murcutt’s... Glenn Murcutt is recognised as one of the most influential architects of the last few decades. His design philosophy, environmental awareness and in-depth understanding of the Australian context and vernacular architecture, have made him one of the leaders of critical regionalism worldwide. His buildings not only provide shelter, but also offer comfort with lower environmental impacts through simple, yet creative design solutions. Although Murcutt’s architecture is well documented, limited evidence-based research has been undertaken to study his approach to design and how this has a direct influence on visual and thermal comfort in his buildings; this paper aims to fill this gap. In this work, the authors have conducted a critical review of three of his most celebrated projects from the environmental design perspective, Marie-Short, Ball-Eastaway, and Marika-Alderton Houses. Even though these houses share a similar building typology, their time of design, location, climate, orientation, tectonics and environmental requirements greatly differ, offering an opportunity for comparative analysis. Through theoretical qualitative and quantitative studies, the close connection between the spatial qualities, environmental design strategies and performance of these houses were investigated in detail. The impact and implications of the reinterpreted elements of Australia’svernacular architecture including verandahs, overhangs, roofing shape, building form and layout, had on the performance and spatial delight of the houses was explored through computer aided modelling. Daylighting and thermal performances were assessed and analysed in correlation with Murcutt’s environmental design strategies. Through this investigation it is clear that while cross-ventilation and shading devices were adopted in buildings to prevent excessive solar ingress during summertime, Murcutt seems to consciously favour scenic views, and a constant connection with nature over visual and thermal comfort. Although the three houses experience occasional visual and thermal discomfort, the research findings suggest that they perform well as free-running buildings for most of the time. They are found to be sensibly designed to be climatically adaptable, skilfully built and spatially delightful, whilst keeping a continuous dialogue with nature; it is achieving this unique balance that lies the significance of Murcutt’swork. Keywords: Critical regionalism, Spatial delight, Climate responsive buildings, Environmental comfort Introduction which is a foreign architectural language, which didn’t The significance of Murcutt’s work derived from the seem to respond well to the Australian context. Fromonot accumulation of lifelong experimentation and experi- [7] further stated that, once Murcutt realized the ences in designing and building climate responsive importance of understanding the impacts of Australia’scli- buildings. During his first years in practice, Mies van der mate and landscape on architecture, he then analysed and Rohe’s influence on Murcutt’s work was significant. The reinterpreted the key elements of Australian vernacular Laurie-Short house, as described by Fromonot ([7], p. 92) architecture and the indigenous life to achieve design was a Meisian styled transparent glass and steel box, solutions that responded to the Australian contexts. While the influence of modern architecture is irrefutable, the combination of Thoreau’s life principles, of living a * Correspondence: Dik.Jarman@nottingham.ac.uk modest life in permanent contact with nature and Department of Architecture and Built Environment Faculty of Engineering, University of Nottingham University Park, NG7 2RD, Nottingham, UK Murcutt’s environmental awareness and profound Full list of author information is available at the end of the article © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Lecaro et al. Future Cities and Environment (2017) 3:3 Page 2 of 18 knowledge of the Australian context and vernacular Kempsey, NSW. Considering the site’s location and the architecture, shaped his work [7]. As explained by Beck locally available building materials, Murcutt opted to re- and Copper [1], it is in this theoretical and physical interpret the simple design of the traditional Australian context that Murcutt convincingly designed responsive woolsheds (Fig. 3) by producing a design whose form buildings, whose elements are assembled ‘responsibly and materiality responded well to the specific site and to the land’ while harmonizing and merging with the climatic conditions. Australian landscape. Through building the Marie-Short House, which is a Considering Murcutt’sextensive oeuvre,thisstudy significant landmark in his career, Murcutt discovered focused on assessing three of his most renowned projects his own architectural language. as a research vehicle to understand the spatial delight and In order to provide further evidence and evaluate the environmental performance of his buildings, the Ball- overall performance and spatial delight achieved in the Eastaway house in New South Wales, the Marika-Alderton Marie-Short House, performative analysis and simula- house in the Northern Territories and the Marie-Short tions were undertaken. In order to holistically identify House in Northern Coastal New South Wales were chosen the effect that natural ventilation, shading devices and for this study. These houses were selected based on their the reinterpreted vernacular elements had on the per- similar building typology and the distinctive site contexts, formance and spatial quality of the house, both luminous with an aim to holistically assess the relation between and thermal environments were studied through detailed Murcutt’s environmental design practice and its impacts on computer aided modelling. In the performative analysis, the buildings’ spatial quality and comfort conditions. Brisbane’s (Queensland) weather file was used for all The research process started with a qualitative analysis simulations, as the closest weather file available. Midday for the three houses by exploring their local climate on 1st of January, the warmest day of the year, was se- (based on weather data from NatHERS in Richmond, lected to investigate the worst case scenario, and used to NSW and Darwin, NT) orientation, spatial arrangement determine the influence of Murcutt’s environmental de- and materiality, aiming to understand Murcutt’s archi- sign principles on the comfort conditions of the house. tectural design principles and how they respond to the Murcutt’s profound understanding of the site (its land- specific site contexts; then, a quantitative analysis was scape, views and climate conditions), led him to design a conducted by computer aided modelling (in Autodesk’s house whose main function was to provide shelter, while Ecotect, Radiance and EDSL TAS), to comprehend the allowing its internal spaces to be adjusted according to luminous and thermal environments of key spaces (i.e. their inhabitants needs. During summer, he considered living rooms and bedrooms). the heavy rains and high temperatures, which conse- Murcutt’s understanding of the Australian climate and quently would induce significant level of humidity; landscape contributes to the development of several key Murcutt also recognised that winter was mild and solar design principles, which he skilfully applies and readapts access would be his main concern. Murcutt’s in-depth in each project. Among his basic design principles, knowledge of the site’s climate, seemed to have led him building orientation (facing north) is essential, as it de- instinctively to overlay the traditional elongated wool- fines two fundamental design aspects: access to sunlight shed, with the lean aboriginal bark shelter on stilts, as a and prevailing winds. Additionally, Murcutt closely stud- new, reinterpreted building typology (Fig. 4); one which ies the site’s geomorphology and views, (Fig. 1) in order once raised off the ground ‘…also enhances airflow and to make an informed decision on the building’s setting. ventilation’ (Beck and Copper, [1]). Once these key aspects were defined, Murcutt studied As Fig. 4 above illustrates, the final design is composed the rainfall and solar angles to design the roofing and by two symmetrical modular wings, (one north oriented, overhangs shape and dimensions. In his buildings, he the other facing south) connected through a central favours slim spaces with a standard height (commonly corridor that acts as a rain gutter; both modules are 2.10 m.) and permeable, lightweight building skins based staggered and raised from the ground on wooden stilts; on vernacular architecture and aboriginal traditional the roof shape and overhang’s responds to the solar alti- shelters (Fig. 2); these spaces are then complemented by tude (84.8°) in summer solstice at noon, in order to pre- the reinterpreted building elements, (i.e. verandahs, vent direct solar ingress into the interior. According to clerestory windows, glazing louvres and blinds) whose Murcutt, designing two separate wings decreased the form, function and materiality are intended to act as the project’s scale and if relocation is needed, disassembly catalysts for Murcutt’s responsive architecture. will be possible; in addition, he “wanted the quality of living to be close to the edge, and to enjoy the landscape Spatial delight in the Marie-Short house views” [1]. This link between the inside and outside is In 1975, Murcutt was commissioned to design the maintained throughout the building, by introducing Marie-Short house located in farmland near the coast of openings on both main facades with glazed louvres and Lecaro et al. Future Cities and Environment (2017) 3:3 Page 3 of 18 Fig. 1 Left: Orientation as a basic design principle, allows the project to benefit from sunlight and prevailing winds. Right: Site analysis based on Glenn Murcutt’s sketches. Heath [8] blinds, providing the inhabitants the control of the Murcutt was seemingly conscious of the environmental amount of daylight and fresh air entering the building. implications of this alteration. When examining the The northern wing (facing the sun), contains the luminous environment of each wing, (while overlapping house’s main living spaces (i.e. main bedroom, dining the sun path diagram) as Fig. 6 illustrates, Murcutt room and kitchen) whereas, the southern wing contains intentionally arranged the spaces, so that the northern the secondary bedrooms and a more secluded living (and public) wing received sunlight throughout the year. room. The central corridor is vital, as the pivot-hinged doors connect the main social spaces, while improving Daylight assessment of the Marie-Short house the conditions for cross ventilation. At the end of the In order to assess the daylighting performance of this corridor, both wings are buffered by verandahs, which house during summer, the house’s main spaces, (i.e. living act as shading devices. rooms and bedrooms) were analysed under an overcast When analysing the house’s current layout, it shows sky condition, on 1st March (warmest day), with all the that Murcutt positioned the main bedroom to the east, blinds fully opened. In this study, both the daylight factor waking up the building occupants by the morning sun and daylight illuminance were analysed and compared. and exposing the space to the morning heat gains as As shown in Fig. 7, the northern living room (NLR) well. However, as shown in Fig. 5, the original layout achieved an average daylight factor of 5% and an illu- was conceived differently, as two wings with distinctive minance level greater than 650 lux towards the exterior uses, (i.e. north wing contained social spaces, while the and lower than 150 lux near the back wall. Whilst the southern wing, the bedrooms) and therefore, with differ- relatively high daylight factors (between 5% to 9%) indi- ent spatial needs and environmental performances. cate that there is no need for artificial lighting for most The current northern wing, was designed to receive time of the year, and the illuminance levels exceed sunlight and prevailing winds, whereas the southern wing CIBSE’s Code for Interior Lighting [5] recommendations. was intended as a relaxing area thus, sheltered from direct However, the high illuminance contrast between the ex- exposure to sunlight and heat gains. After the extension, terior and the back wall, could potentially cause visual Fig. 2 Left and middle: Australian aboriginal bark shelters on stilts (off the ground). From Lee [12]. Right: Australian veranda. From, West End Cottage [11] Lecaro et al. Future Cities and Environment (2017) 3:3 Page 4 of 18 Fig. 3 Left: Traditional Australian woolshed. Murray Johnson. Right: Marie-Short House (1980). Richard Powers discomfort (i.e. glare) unless the internal blinds are 4.5%, whereas the illuminance levels rapidly increase drawn. from 150 lux in the centre, to 750 lux towards the Given the difference in the orientation of the southern windows. Although artificial lighting was needed as a living room (SLR) and the North Living Room (NLR), supplementary light source, the risk of visual discomfort different daylighting performance were expected. As might occur, but this The southern bedroom (SB), was shown in Fig. 7, surprising results were obtained for the strategically positioned by Murcutt to receive more daylight simulations, while the average daylight factor direct sunlight (and heat gains) throughout the year a was of 9%, the illuminance levels on the interior sur- (see Fig. 8). The average daylight factor was 9% (indicat- faces, ranged between 250 and 750 lux. Despite daylight ing no artificial lighting is needed), while the illuminance is more uniformly distributed when compared to NLR, levels ranged similarly to the NB, (i.e. between 150–750 (as it receives both indirect light from the exterior, and lux) suggesting internal blinds are needed to reduce the direct light from the skylight Murcutt designed for this high illuminance contrast and reduce the risk of glare. space), the light levels indicate the potential risk of visual discomfort too. Thermal assessment of the Marie-Short house The bedroom areas, given their use and arrangement To assess the thermal conditions in the selected spaces were expected to perform differently from the living (during summer), a model of the house was built in EDSL rooms previously assessed. As shown in Fig. 8, the aver- TAS, distributing each space as a separate thermal zone age daylight factor for the northern bedroom (NB) was (Fig. 9), and analysing the connection between their Fig. 4 Top: Current layout of the house, by Ozetecture (2013). Bottom: Sun, wind and rainfall analysis in the MSH Lecaro et al. Future Cities and Environment (2017) 3:3 Page 5 of 18 Fig. 5 Original layout (1975) and current layout after renovation (1980). Layouts by Murcutt [13] resultant temperatures in relation to their openings, no natural ventilation, case 2 as the worst possible sce- building materials and adjacent buffer zones (i.e. ve- nario with internal heat gains but without natural ventila- randahs). These thermal simulations were performed tion; cases 3 and 4 represented the best possible scenarios, from day 355 until day 80, corresponding to the and natural ventilation was introduced initially by having Australian summer time. a 50% effective aperture, and then a 95% effective aperture The assessment considered four possible cases (Table 1), to the openings, so that a clear understanding of the all having a constant natural infiltration rate of 0,25 ACH impact of natural ventilation on thermal comfort can be and shading as designed, but varying in the levels of in- obtained. ternal heat gains and natural ventilation rates. Case 1 was The following assumptions were considered for the set up as a base example with no internal heat gains and simulations: Fig. 6 Time and spatial arrangement. Sunpath analysis during summer solstice, equinox and winter solstice Lecaro et al. Future Cities and Environment (2017) 3:3 Page 6 of 18 Fig. 7 Daylight performance comparison between living rooms. DF (%) and Illuminance assessment in ECOTECT and Radiance Fig. 8 Daylight performance comparison between bedrooms. Daylight Factor (%) and Illuminance assessment in ECOTECT and Radiance Lecaro et al. Future Cities and Environment (2017) 3:3 Page 7 of 18 Fig. 9 Thermal zoning of key spaces for simulation in the Marie-Short house. Thermal assessment in EDSL Tas Weather: Energy Plus weather data for Brisbane, occupied and set to start opening when the Queensland. temperature reached 25 °C and to be fully opened Comfort range: during summer it was assumed to at 28 °C. be between 25 °C to 28 °C.  All the cases included shading from the blinds and Calendar: summer period was assumed to be from verandahs. the 21st of December until the 22nd of March. Internal Gains: the following values were assumed: Similar to the analytical methodology adopted in the ○ Three people occupying the house, whose heat daylighting performance analysis, thermal analysis re- gains were assumed to be 120 W per person, sults were compared in each thermal zone with similar 75 W sensible and 45 W latent. activities, with an aim to exam the correlations among ○ The occupancy schedule was set assuming a them. The results were presented as a percentage of weekly work schedule, were occupancy is highest time when the resultant interior temperatures were during sleep time and falls during daytime, ranged between 25 °C and 30 °C. experiencing peaks during early morning (6-9 am), As Fig. 10 shows, both living rooms present different lunch (12-2 pm) and evenings (5 pm onwards). thermal performances. It is important to emphasize, that Lighting: compact low-energy florescent bulbs with while both zones have a similar area, the heat gains vary a 25 W thermal load per light bulb, with a total load greatly, as the northern living room includes the heat of 9 W/m gains from kitchen’s appliances. Equipment and appliance gains: equipment’s considered were a hob, a washing machine, a  Case 1: in both zones, only 45% of the occupied dishwasher and a fridge, all with a total load of hours are above the comfort range. 27 W/m .  Case 2: the addition of internal heat gains while the Infiltration rate: was considered to be 0.25 ACH in envelope remains closed, (without any ventilation) all zones. led to a significant increase in the number of hours Ventilation: all openings have the same opening outside the comfort range in both zones. In the patternduringthe periodswhenthe house was NLR, over 48% of the occupied hours are outside the comfort range, while for the SLR, over 84% of the occupied hours are outside the comfort range, Table 1 Summary of thermal cases examined indicating that the building envelope and shading Presence Presence Presence Presence devices alone are not adequate to offer desirable (Yes/No) (Yes/No) (Yes/No) (Yes/No) thermal comfort in this building. Internal heat gains NO YES YES YES Case 3: 50% of effective aperture in doors and Natural ventilation NO NO YES (50%) YES (95%) windows significantly increased the number of hours Case 1 2 3 4 within the comfort range for both zones, proving Lecaro et al. Future Cities and Environment (2017) 3:3 Page 8 of 18 Fig. 10 Thermal performance comparison in living rooms. Thermal assessment in EDSL TAS that natural ventilation work as intended. The the exposed facades provided by the verandahs, simulation results also show that for over 60% of the However 35% of the occupied hours are still outside time, the resultant temperatures are within the the comfort range. comfort range.  Case 2: the results indicated that the addition of Case 4: 95% aperture in openings did not internal heat gains (while the envelope is closed), do significantly improve what was achieved in the not significantly affect the number of hours the previous case and comfort condition is achieved for bedrooms are within the comfort range (over 50%). over 60% of the occupied hours, indicating that a The spatial arrangement of these spaces within the partial effective aperture of the openings (in Case 3) house is the key to attain the thermal comfort levels. is sufficient to cool down the internal temperatures.  Case 3: 50% of aperture in doors and windows increased the number of hours (above 70%) for the Thermal performance in both bedrooms shows a com- resultant temperatures fall within the comfort range parable trends as shown in Fig. 11. in the bedrooms, indicating that natural ventilation improves the thermal comfort. Case 1: in both zones, the percentage of achieving  Case 4: A 95% of aperture in openings, slightly comfort levels without any ventilation present is increased the number (above 75%) of hours for the over 65% of the hours; this is due to the shading on resultant temperatures fall within the comfort range, Lecaro et al. Future Cities and Environment (2017) 3:3 Page 9 of 18 Fig. 11 Thermal performance comparison in bedrooms. Thermal assessment in EDSL TAS showing that higher effective aperture is essential to the interior spaces were clearly defined between served improve the thermal comfort of these spaces. spaces (i.e. bedrooms), positioned to the SW and serving spaces (i.e. living space) to the NE, intending to position Spatial delight in the Ball-Eastaway house the main spaces in contact with the exterior. Completed in 1983, the Ball-Eastaway house is located The section derived from a thoughtful site analysis, at a remote bush land in Glenorie, NSW (33.6° S) and it when the site’s high rainfall and surrounding trees were was designed as a retreat and workspace for its artist considered, Murcutt recognised that conventional gut- owners. Murcutt intentionally positioned the house over ters and pipes would block, therefore a vaulted, corru- a sandstone bed, and changed his distinctive preference gated iron roof with broad gutters was his response for north orientation to exploit the site’s views and to (Fig. 13). Additionally, he favoured a light-weighted steel create a more peaceful atmosphere (Fig. 12). structure, (minimizing the use of timber) and corrugated As suggested by Farrelly [6], this house’s configuration iron exteriors, contrasting with the natural setting and responds to the sandstone’s bed shape, which offered the softer and warmer interior. Murcutt the opportunity to lift the house off the ground According to NatHERS (2014), the site experiences a on steel stilts (Fig. 12), protecting the building from seasonal climate with temperature range between 39,5 °C wildfires while providing a less invasive building process; (January) and 0 °C (August) and a monthly mean rainfall Lecaro et al. Future Cities and Environment (2017) 3:3 Page 10 of 18 Fig. 12 Left: Exterior view by Max Dupain. Source: Levene and Marquez [10]. Right: Plan and spatial arrangement ranging from 122 mm (February), to 28,5 mm (July); Daylight assessment of the Ball-Eastaway house therefore the building’s orientation and envelope are es- To assess the daylighting performance of the house’s sential to cope with the site’s climatic conditions. main spaces, (i.e. living room and bedroom) and to en- When the building’s orientation is analysed in relation sure that the spaces were adequately day-lit, a target to the sun path diagram, Murcutt’s intention of favour- daylight factor of 2%, based on BSI [3] standard guide- ing the site’s views over a valuable north orientation is lines, was chosen to analyse their daylighting perform- evident. As Fig. 13 shows, the house’s orientation ex- ance under overcast sky conditions. As shown in Fig. 14, posed the public areas to partial sunlight ingress in the the average daylight factor in the main spaces was above morning, while underexposed the private ones at the 5%, indicating that all spaces are well-day lit and no sup- same time. According to NatHERS (2014), the optimum plementary lighting from artificial sources is needed as orientation would convey in better solar access (and heat CIBSE [4] established. gains) during winter, while providing a better opportun- The uniformity ratios and light journey achieved (Fig. 14) ity to exploit the site’s prevailing winds during summer. in the internal spaces, showed that Murcutt designed and When the house’s section is overlapped with the solar positioned the openings intentionally to create a dynamic, angles during equinox and solstices at noon, it is clear that yet relaxing atmosphere. Despite the house’s orientation is the roof was not intended to respond to the sun (Fig. 13), not optimum, Murcutt was able to make a clear transition reinforcing the argument that orientation was not a prior- between the living space and the bedrooms. The most dra- ity here; nevertheless, the roof still provides shelter from matic variation can be perceived in the main entrance, the summer sun at noon and the associated heat gains, where the daylight factor drastically lowered providing vis- while admitting partial solar access during winter. As a ual adaptation to the inhabitants through the corridor. free-running building, the house was designed to be To investigate the illuminance distribution within the cooled by natural ventilation, hence Murcutt raised it house’s most occupied space (i.e. living room), daylight off the ground intending to improve cross-ventilation illuminance was assessed at noon under sunny sky and reduce internal temperature during summertime. (Equinox) and overcast skies conditions, to have a Fig. 13 Left: Ball-Eastaway’s orientation vs. sunpath during winter and summer solstice and optimum orientation. Source: NatHERS (2014) Right: Section vs. solar access at noon during summer solstice, equinox and winter solstice Lecaro et al. Future Cities and Environment (2017) 3:3 Page 11 of 18 Fig. 14 DF plot and section, uniformity ratios and light journey in the Ball-Eastaway house broader understanding of its performance. The results blinds or external architectural features were included, a were compared to CIBSE [4] 300 lux recommendation. more visually comfortable space could be provided. As Fig. 15 illustrates, the high illumination levels (+680 lux average without internal blinds) present dur- Thermal performance and spatial delight in the ing sunny sky conditions in Equinox, indicates that while Ball-Eastaway house the space is well day-lit, an over-lit environment or vis- Evaluating the thermal environment of the house was essential ual fatigue might be experienced; under overcast sky to have a full understanding of the building’s performance and conditions, the average illuminance levels significantly its impact on comfort, especially when Murcutt’sprojectsare decreases to 280 lux, indicating adequate daylight illu- designed as free-running buildings, with operable envelopes minance is provided for visual perception; However, in designed to adapt to the climatic challenges. As Kallenbach [9] both cases, the high illuminance levels achieved towards echoed Murcutt’swords ‘[just as] we layer our clothing…our the opening indicate that, the use of blinds or operable buildings should equally respond to their climates.’ shading devices is needed for improving the luminous Since this house’s orientation and spatial arrangement environment. pointed to an unlikely positive thermal performance, a To assess the luminous intensity, the brightness con- model of the house was built in EDSL TAS, distributing trast ratio was used to evaluate whether the house pro- each space as a separate thermal zone (Fig. 17); simula- vides visual comfort for its occupants in the living room. tions were performed aiming to have an overall idea of Although the sky conditions on site are mostly overcast, the annual thermal performance in key spaces, neverthe- the luminance mapping was performed under both, less, analysing winter’s performance was essential and sunny (Equinox) and overcast sky conditions, so that a the chimney’s heat transfers were considered. more realistic luminous environment could be evaluated. The assessment considered three possible cases (Fig. 17), Murcutt designed the corridor as an exposition area all having a constant natural infiltration rate of 0,50, shad- for paintings, offering the best target for brightness con- ing as designed and varying in the levels of internal heat trast assessment. As Fig. 16 shows, the visual target con- gains and natural ventilation rates. Case 1 was set up as a sidered does not suffer from major visual discomfort; base example with no heat gains and no natural ventila- however, as the results demonstrate, if the target is tion; Case 2 as summer’s scenario with natural ventilation shifted towards the dining room, the luminance contrast and heat gains; Case 3 represented winters’ scenario and might significantly change, implying that under these all internal heat gains were included and natural ventila- sky conditions the inhabitants may suffer from glare. If tion was set to occur only if the resultant temperatures Fig. 15 Illuminance (lux) plots at noon under sunny sky (Equinox) and overcast sky conditions Lecaro et al. Future Cities and Environment (2017) 3:3 Page 12 of 18 Fig. 16 Luminance (cd/m2) assessment at noon under sunny sky (Equinox) and overcast sky conditions surpassed the established comfortable temperature Thermal analysis results were compared between both range. Aperture variation in openings was considered thermal zones, comparing seasonal thermal performance to recognise the influence of natural ventilation on vs. average resultant temperatures to examine the correla- thermal comfort. tions. Results wereshown as apercentageoftimewhenthe In order to define a comfort zone, monthly average tem- resultant interior temperature ranged between 19 °C to 23 ° peratures were used as a base to calculate the optimal Cinwinter, and22°Cto 27°Cinsummer. As Fig. 18 temperature for comfort (i.e. T )inRichmond, NSW, shows, both spaces share a similar thermal performance; comf based on the Adaptive Model by Nicol et al. however, during winter, the living room’s performance im- The following assumptions were considered for the proved while the bedroom’s performance becomes worse. simulations: The following conclusions were drawn from this analysis: Weather: Energy Plus weather data for Richmond,  Case 1: Annually, 20% of the occupied time in the New South Wales. house falls within the comfort zone, (except during Comfort range: winter between 19 °C to 23 °C, and winter when performance falls to 15%), inferring 22 °C to 27 °C during summertime. heat gains are essential to improve the thermal Calendar: Annual performance. Internal Gains:  Case 2: The thermal comfort in the internal spaces is ○ Occupancy: two adults with heat gains assumed within the comfort range for 25% of the time; despite to be of 180 W (sensible) and 100 W (latent). heat gains improved the percentage of time within the ○ The occupancy schedule was set for 24 hours. comport range, resultant temperature was 17 °C Lighting: compact low-energy florescent bulbs with (below comfort); in summer, natural ventilation can a total load of 2,5 W/m help improve the thermal environment as the Equipment gains: hob, a washing machine, a dishwasher predicted resultant temperature reached 22 °C. and a fridge, all with a total load of 25 W/m .  Case 3: represented the best scenario during winter Chimney sensible gains of with a total load of 40 W/m . for the living room, while unexpectedly the worst Ventilation: during occupancy periods all openings for the bedrooms; the chimney’s heat gains seem to had the same opening pattern; starting to open have a significant impact on the living room’s when the temperature reached 19 °C and fully thermal performance, but seemingly the envelope’s opened at 27 °C. airtightness is not enough, as heat gains from the Fig. 17 Left: Thermal assessment and zoning of key spaces in the Ball-Eastaway house. Thermal assessment in EDSL Tas. Right: Summary of thermal cases examined Lecaro et al. Future Cities and Environment (2017) 3:3 Page 13 of 18 Fig. 18 Seasonal thermal performance of main spaces vs. average exterior and resultant temperatures chimney seemingly do not reach the bedrooms. while arranging the spaces responding to aboriginal trad- During summer there was no perceptible ition, with the adult’s room positioned to the West, where improvement, indicating that natural ventilation by thesun sets, whilethe children’s bedrooms are located to itself is not enough to dissipate the internal heat the East, where the sun rises symbolizing new life. In this gains. Annually both spaces performed thermally at project, Murcutt converged and materialized his life learn- an average of 30% of the occupied time. ings on Thoreau’s philosophies, with the lessons learnt from vernacular architecture and aboriginal way of life, Fromo- Spatial delight in the Marika-Alderton house not [7]. The Marika-Alderton house is positioned by the seaside in The house’s section was conceived to fully respond to the Eastern Arnhem, NT (12.5° S) and was completed in 1994. site’s tropical climate, (i.e. harsh sunlight, high tempera- According to Beck and Copper [1], the house was designed tures, humidity levels and occasional cyclones) while pro- for an aboriginal family intending to create a dwelling that viding visual connection with the exterior; Murcutt followed native traditions, while providing shelter from cli- conceived a slim, symmetrical section (Fig. 19) raised off mate. Murcutt oriented the house facing north (Fig. 19), the ground on steel pillars to improve the effect of natural Fig. 19 Left: Marika-Alderton house. Photography by: Reiner Blunck. Source: El Croquis (2013). Right: Spatial arrangement and section vs. solar angles Lecaro et al. Future Cities and Environment (2017) 3:3 Page 14 of 18 ventilation, while the roof’s long overhangs protect the in- skies conditions; results were compared to CIBSE [4] terior from sun and rain. An operable and permeable enve- 300 lux recommendation. lope, (composed by slatted shutters, doors, tilting plywood As illustrated in Fig. 22, under sunny sky conditions panels and sun breakers) ensures a constant flow of fresh during Equinox, shading devices completely protect air, while the sun breakers provide shading to all bedrooms surfaces from direct sunlight, yet the high light levels from low-angled southern sun. (+600 lux average) indicate that even if the space is well When the envelope and structure’s materiality is ob- day-lit, visual fatigue may be experienced, suggesting served, the pragmatic and unpretentious intentions of that if the operable openings were closed, this condition Murcutt is clear. By using modest building materials such might considerably improve; however, under overcast as steel, timber, plywood and corrugated iron, it is possible sky conditions, the illuminance levels achieved between to orchestrate a space that adapts accordingly to climate. 250 – 300 lux in average, indicating desirable luminous According to BOM [2], the site experiences constant environment with good level ofvisual acuity. high temperatures (18 °C to 35 °C), humidity, rainfall, According to the results of the brightness contrast solar radiation levels and occasional cyclonic winds, thus analysis (Fig. 23), the brightness contrast ratio between while encouraging natural ventilation, blocking undesired the visual tasks and their surroundings proved that ex- sunlight is required. As Fig. 20 shows, the house’sorienta- periencing visual discomfort is unlikely to occur. The tion as designed is very close to the optimum orientation. careful selection of building materials with relatively low Murcutt merged the outside and inside, with an aim to reflectance (i.e. mostly wood in the interior), decreased cool down the interior through natural ventilation and the chance of experiencing visual discomfort. Neverthe- shading; nevertheless, its permanent contact with the ex- less, this study was performed considering all shutters terior makes the building dependent on exterior tempera- remained opened (as worst case scenario); if they were tures to achieve comfort, hence an increase in wind speed closed, the risk of visual discomfort would be signifi- is necessary conscious of this, Murcutt included in the cantly reduced. roof several Windworkers designed to increase air flow within the house, encouraging natural ventilation and the Thermal performance and spatial delight in the extraction of heat trapped in the roof (Fig. 20). Marika-Alderton house The constant permeable nature of the house was consid- ered, as it is dependent on the exterior thermal environ- Daylight assessment of the Marika-Alderton ment and wind to cool down the interior. Additionally, house the shallow envelope (built on elements with low ther- Following the methodology described in the above case mal properties), and warm air been constantly pushed study, the daylighting performance of the house’s main into the house were taken into account. spaces, was investigated under overcast sky conditions. To assess the thermal conditions, a model of the house As Fig. 21 shows, the average daylight factor in the main was built in EDSL TAS (Fig. 24), distributing each space spaces ranged from 3% to 5%, indicating that most of as a separate thermal zone. The simulations were the spaces are well-day lit and artificial lighting is re- performed aiming to have an overall idea of the annual quired for most of the time. Additionally, the light jour- performance of the main living spaces and to provide ney graph indicates a continuous variation in daylight, evidence on the effect that solar radiation, natural venti- ranging from a vivid atmosphere in serving spaces, to a lation and internal heat gains had on the resultant calmer one in the bedrooms. temperatures annually. In order to have more realistic The daylight illuminance was assessed in the living results, the Windworkers’‘Venturi’ effect was simulated space, at noon under sunny sky (Equinox) and overcast by adding opaque openings to the roof. Fig. 20 Left: Spatial arrangement and sunpath during winter and summer solstice; Optimum orientation. Source: NatHERS and Autodesk Ecotect’s weather tool (2014). Right: air movement and cross-ventilation produced by Windworkers Lecaro et al. Future Cities and Environment (2017) 3:3 Page 15 of 18 Fig. 21 DF plot and section, uniformity ratios and light journey in the Marika-Alderton house. Source: Authors The assessment considered three possible cases (Fig. 24),  Ventilation: opening schedule is based on all having as constants: shading, natural ventilation (vary- occupancy, partial natural ventilation is allowed ing accordingly to each case) and infiltration rate 0,50; 24 hours a day. heat gains were the only variants. Case 1 was set as a base example with partial natural ventilation and no heat gains; Thermal analysis results were compared between both case 2 represented the worse scenario, as heat gains were zones, relating seasonal thermal performance vs. average included; case 3 was designed as the best possible sce- resultant temperatures. Results are shown as a percent- nario, as natural ventilation was increased to have a stron- age of time when the resultant interior temperature ger perspective on the influence natural ventilation had on ranged between 23 °C to 28 °C; yet the consequences of thermal comfort. the house being an open space have to be considered. Setting a comfort zone for this analysis, followed the As Fig. 25 shows, both spaces shared a similar thermal same principles, equations and guidelines described in performance; annually none of the spaces reached a 30% teh above case study, based on the optimal temperature of time within the comfort range, having significantly high for comfort (i.e. T ) in Darwin (NT), and based on resultant temperatures fluctuating between 27 °C to 35 °C. comf the Adaptive Model by Nicol et al. The following conclusions were drawn from the analysis: The following assumptions were considered for these simulations:  Case 1: 20% of the occupied hours in a year are within the comfort range (without any heat gains). Weather: Energy Plus weather data for Darwin, NT. During winter the thermal performance fell with Comfort range: assumed to be between 23 °C to 28 °C 16% of the occupied hours falling within the Calendar: Annual comfort zone. Internal Gains:  Case 2: Presented an insignificant improvement ○ Occupancy: 2 adults and 4 children; heat gains when compared to Case 1; only a 3% increase of the assumed 450 W (sensible) and 250 W (latent). time within the comfort zone was experienced when ○ The occupancy schedule was set assuming a natural ventilation was introduced; overheating 24 hours. could be experienced and extra cooling is needed. Lighting: compact low-energy florescent bulbs with  Case 3: The comfort range slightly increased to 25% a total load of 1,5 W/m when twice the air flow was introduced, still the Equipment gains: equipment’s considered were a building is unable to rapidly exhaust warm air hob and a fridge, with a total load of 25 W/m . trapped under the roof, leading to overheating. Fig. 22 Illuminance (lux) plots at noon under sunny sky (Equinox) and overcast sky conditions Lecaro et al. Future Cities and Environment (2017) 3:3 Page 16 of 18 Fig. 23 Luminance (cd/m2) assessment at noon under sunny sky (Equinox) and overcast sky conditions Overall, the thermal performance of both spaces is poor, depth contextual knowledge is overlaid with his main only 30% of the occupied hours in a year are within the environmental design strategies, (i.e. orientation, nar- comfort range, demonstrating it potentially needs mech- row plans with climate-responsive sections, natural anical cooling; however, the thermal conditions could po- ventilation, shading and light-weighted operable skins) tentially be improved and moderated by the occupants’ an architecture that adapts to the local climate and site control of the building’s operable envelope. conditions is born. When the luminous environments in the three selected Conclusion buildings were analysed, they proved to be mostly well Through an in-depth analysis of each house, supported day-lit, nevertheless throughout all projects assessed, in by the factual evidence gathered from qualitative and order to improve visual comfort, shading devices (such as quantitative analysis, the authors have attained a holistic blinds, shutters or sun breakers) need to be constantly understanding of Murcutt’s architectural achievements, deployed. However, Murcutt’s skilful way of handling day- the reasoning behind his design approach and building light produced subtle light journeys in the houses, which solutions. Moreover, the authors have outlined the sig- offers variation in intensity depending on the spatial func- nificant impact that Murcutt’s design intents have on the tion and intended atmosphere, ranging from vibrant light visual and thermal comfort of his buildings. in public spaces, to soothing light in private ones. From a qualitative perspective, not only were Murcutt’s For the thermal environments in his houses, the thermal design intentions revealed, but also, the intrinsic connec- analysis revealed occasional thermal discomfort. Consider- tion he proposed between the manmade space and nature ing the houses’ envelopes as designed, the results showed were presented. Through simple forms and humble mate- that in the Ball-Eastaway house, the thermal performance rials, Murcutt merges his buildings with nature, not im- of the main spaces fell below an annual average of 30% of plying the superiority of one over the other, but through the occupied time within the comfort range, suggesting unity, his architecture constantly reminds us the signifi- that improving the envelope’s insulation and airtightness, cance of nature. combined with extra heating (for winter) could potentially Detailed site-specific climate analysis including the solar improve the house’s thermal comfort. In the Marika- trajectory, prevailing winds, rainfall and landscape, is Alderton house, which presented an annual average of Murcutt’s essential first step in dealing with a design chal- 25% of the time within the comfort range, showing that lenges. When all these factors combine, nature seems to even when the Windworkers was used to increase the air speak and guide him to define forms and spaces that movement, the main spaces still experienced overheating are translated into climate responsive, potentially free- which is caused by the fact that the building’s envelope running vernacular inspired architecture. Once this in- was designed to be light-weight and the roof is not Fig. 24 Left: Thermal assessment and zoning of key spaces in the Marika-Alderton house. Thermal assessment in EDSL Tas. Right: Summary of thermal cases examined Lecaro et al. Future Cities and Environment (2017) 3:3 Page 17 of 18 Zone Frequency (%) of hours in comfort zone vs. seasonal average resultant temperatures. Fig. 25 Seasonal thermal performance of main spaces vs. average exterior and resultant temperatures insulated. However, occupants’ active control of the oper- changes and adapts to the climate and its inhabitants able building envelopes might potentially help reduce cer- needs. tain degree of overheating in summer. The spatial and environmental delight in Murcutt’s In the Marie Short house, Murcutt’s environmen- buildings lies in this delicate relationship between tal design strategies, (i.e. orientation, natural ventila- providing an enriching spatial experience (through a tion, shading and designing a light weighted constant connection with nature), and at the same time building, raised off the ground on stilts) created a offering desirable comfort conditions. Through his low energy building, which constantly interacts with pragmatism, Murcutt designed buildings responding to theoutside,and offers theinhabitants theopportun- the site conditions and climate. Through the balance ity to dictate how to operate and adapt their spaces. between man and nature, Murcutt’s buildings are vivid, Undoubtedly as the results demonstrated, in order healthy and delightful, but more importantly, they are to maximise thermal comfort the key living spaces designed to be operable and constantly influenced by are dependent on natural ventilation, as the shading the external conditions, in order to allow the inhabi- alone will not significantly decrease the resultant tants to fully experience and control their space. temperatures. On the other hand, even though It is important to reflect that Murcutt designed these Murcutt provided the main facades with integrated environmental conscious buildings by utilising unpreten- blinds, the results have shown that if left opened, tious local materials and construction techniques. The the inhabitants will experience visual discomfort, in- constant connecting of his architecture with the natural dicating that even when Murcutt wanted to have a environment, and his unique application of reinterpreted constant connection with nature, reconsidering the vernacular elements such as verandahs, overhangs and opening sizes might help improve the visual comfort narrow spaces with permeable skins combined with and spatial delight of the house. Murcutt’s environmental design strategies has produced When the Marie-Short house is fully investigated and self-reliant, low energy consumption buildings. its performance assessed, Murcutt’s design excellence In the case of the Marie-Short house, its cleverness at and skilfulness are more significant than this building’s first glance is disguised as a modest woolshed. It stands apparent deficiencies. The Marie-Short house has to be lightly, quiet and unpretentious surrounded only by the analysed as a free-running building, which constantly Australian landscape. Through this humble design, Bedroom Living space Lecaro et al. Future Cities and Environment (2017) 3:3 Page 18 of 18 Murcutt transformed a seemingly artless woolshed, into 10. Levene RC, Márquez C (2012) Glenn Murcutt 1980–2012: Plumas de Metal - Feathers of Metal. El Croquis, Madrid a fascinating habitat, allowing its inhabitants to adjust 11. West End Cottage (2012) Verandahs and Sleep outs. http://westendcottage. the spaces accordingly to their needs. Just as Heath [8] blogspot.co.uk/2012/07/verandahs-and-sleepouts_20.html. Accessed 16 May described Murcutt’s work as a choreography, ‘designed 2014. 12. Lee D (2010) Aborigines People. http://warearthissue2010.blogspot.co.uk/ so it can literally be tuned like an instrument to respond 2010/09/aborigines-people.html. Accessed 30 Mar 2017. to seasonal cycles’, the Marie-Short house performed as 13. Murcutt G, The Marie Short House (2014) OZETECTURE. Available at: http:// it was designed to, as a free-running building. www.ozetecture.org/2012/marie-short-glenn-murcutt-house/. Accessed 17 May 2014. Murcutt’s spatial quality transcends from mere aes- thetics into workable, adaptable and pleasing spaces; through his buildings, Murcutt has revitalized (rather than imposing) the vernacular architecture principles and reapply them to create humble, yet site specific and innovative architecture. Abbreviations CIBSE: Chartered Institution of Building Services Engineers; EDSL: Environmental Design Solutions Limited; NatHERS: Nationwide House Energy Rating Scheme (Australia); NB: Northern bedroom; NLR: Northern living room; NT: Northern Territory Australia; SB: Southern bedroom; SLR: Southern living room Funding The author Mauricio Lecaro received a scholarship by the Republic of Ecuador through SENESCYT's scholarship program named "Convocatoria Abierta 2013 - Primera Fase". Authors’ contributions ML did the research, software analysis and initial draft of the paper. LR and BL provided guidance, reviewed and supervised all stages of this study. DJ reviewed and edited the material to generate this technical report. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Publisher’sNote Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Author details Gensler, Avenida Escazú, Torre Lexus, piso 7, San José 10203, Costa Rica. Department of Architecture and Built Environment Faculty of Engineering, University of Nottingham University Park, NG7 2RD, Nottingham, UK. Received: 19 August 2016 Accepted: 28 February 2017 References 1. Beck H, Cooper J (2002) Glenn Murcutt: A Singular Architectural Practice. Edition. Images Publication Group, Melbourne. 2. Bureau of Meteorology, BOM (2014) Climate of New South Wales. www. bom.gov.au/lam/climate/levelthree/ausclim/ausclimnsw.htm. Accessed 23 Aug 2014. 3. British Standards Institution, BSI (2008) Lighting for buildings. Code of Submit your manuscript to a practice for daylighting. B S I Standards, London. journal and benefi t from: 4. Chartered Institution of Building Services Engineers, CIBSE (1994) Code for interior lighting. Chartered Institution of Building Services Engineers, 7 Convenient online submission London 7 Rigorous peer review 5. CIBSE (2002) Code for Lighting, 1st edn. Butterworth-Heinemann, London 6. Farrelly EM (2002) Three houses: Glenn Murcutt. Phaidon, London 7 Immediate publication on acceptance 7. Fromonot F (2003) Glenn Murcutt: Buildings and Projects 1962–2003, 2nd 7 Open access: articles freely available online edn. Rev Sub edn. Thames & Hudson, London and New York. 7 High visibility within the fi eld 8. Heath K (2009) Vernacular Architecture and Regional Design, 1st edn. 7 Retaining the copyright to your article Routledge, London 9. Kallenbach L (2002) Architect Profile: Glenn Murcutt. Available at: http:// www.motherearthliving.com/green-living/nh-natural-home-journal2. Submit your next manuscript at 7 springeropen.com aspx#axzz3BRxfGvyC. Accessed 16 May 2014. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Future Cities and Environment Springer Journals

The application of vernacular Australian environmental design principles in Glenn Murcutt’s architecture

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Energy; Energy Efficiency; Renewable and Green Energy; Energy Technology; Landscape/Regional and Urban Planning
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Abstract

Glenn Murcutt is recognised as one of the most influential architects of the last few decades. His design philosophy, environmental awareness and in-depth understanding of the Australian context and vernacular architecture, have made him one of the leaders of critical regionalism worldwide. His buildings not only provide shelter, but also offer comfort with lower environmental impacts through simple, yet creative design solutions. Although Murcutt’s architecture is well documented, limited evidence-based research has been undertaken to study his approach to design and how this has a direct influence on visual and thermal comfort in his buildings; this paper aims to fill this gap. In this work, the authors have conducted a critical review of three of his most celebrated projects from the environmental design perspective, Marie-Short, Ball-Eastaway, and Marika-Alderton Houses. Even though these houses share a similar building typology, their time of design, location, climate, orientation, tectonics and environmental requirements greatly differ, offering an opportunity for comparative analysis. Through theoretical qualitative and quantitative studies, the close connection between the spatial qualities, environmental design strategies and performance of these houses were investigated in detail. The impact and implications of the reinterpreted elements of Australia’svernacular architecture including verandahs, overhangs, roofing shape, building form and layout, had on the performance and spatial delight of the houses was explored through computer aided modelling. Daylighting and thermal performances were assessed and analysed in correlation with Murcutt’s environmental design strategies. Through this investigation it is clear that while cross-ventilation and shading devices were adopted in buildings to prevent excessive solar ingress during summertime, Murcutt seems to consciously favour scenic views, and a constant connection with nature over visual and thermal comfort. Although the three houses experience occasional visual and thermal discomfort, the research findings suggest that they perform well as free-running buildings for most of the time. They are found to be sensibly designed to be climatically adaptable, skilfully built and spatially delightful, whilst keeping a continuous dialogue with nature; it is achieving this unique balance that lies the significance of Murcutt’swork. Keywords: Critical regionalism, Spatial delight, Climate responsive buildings, Environmental comfort Introduction which is a foreign architectural language, which didn’t The significance of Murcutt’s work derived from the seem to respond well to the Australian context. Fromonot accumulation of lifelong experimentation and experi- [7] further stated that, once Murcutt realized the ences in designing and building climate responsive importance of understanding the impacts of Australia’scli- buildings. During his first years in practice, Mies van der mate and landscape on architecture, he then analysed and Rohe’s influence on Murcutt’s work was significant. The reinterpreted the key elements of Australian vernacular Laurie-Short house, as described by Fromonot ([7], p. 92) architecture and the indigenous life to achieve design was a Meisian styled transparent glass and steel box, solutions that responded to the Australian contexts. While the influence of modern architecture is irrefutable, the combination of Thoreau’s life principles, of living a * Correspondence: Dik.Jarman@nottingham.ac.uk modest life in permanent contact with nature and Department of Architecture and Built Environment Faculty of Engineering, University of Nottingham University Park, NG7 2RD, Nottingham, UK Murcutt’s environmental awareness and profound Full list of author information is available at the end of the article © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Lecaro et al. Future Cities and Environment (2017) 3:3 Page 2 of 18 knowledge of the Australian context and vernacular Kempsey, NSW. Considering the site’s location and the architecture, shaped his work [7]. As explained by Beck locally available building materials, Murcutt opted to re- and Copper [1], it is in this theoretical and physical interpret the simple design of the traditional Australian context that Murcutt convincingly designed responsive woolsheds (Fig. 3) by producing a design whose form buildings, whose elements are assembled ‘responsibly and materiality responded well to the specific site and to the land’ while harmonizing and merging with the climatic conditions. Australian landscape. Through building the Marie-Short House, which is a Considering Murcutt’sextensive oeuvre,thisstudy significant landmark in his career, Murcutt discovered focused on assessing three of his most renowned projects his own architectural language. as a research vehicle to understand the spatial delight and In order to provide further evidence and evaluate the environmental performance of his buildings, the Ball- overall performance and spatial delight achieved in the Eastaway house in New South Wales, the Marika-Alderton Marie-Short House, performative analysis and simula- house in the Northern Territories and the Marie-Short tions were undertaken. In order to holistically identify House in Northern Coastal New South Wales were chosen the effect that natural ventilation, shading devices and for this study. These houses were selected based on their the reinterpreted vernacular elements had on the per- similar building typology and the distinctive site contexts, formance and spatial quality of the house, both luminous with an aim to holistically assess the relation between and thermal environments were studied through detailed Murcutt’s environmental design practice and its impacts on computer aided modelling. In the performative analysis, the buildings’ spatial quality and comfort conditions. Brisbane’s (Queensland) weather file was used for all The research process started with a qualitative analysis simulations, as the closest weather file available. Midday for the three houses by exploring their local climate on 1st of January, the warmest day of the year, was se- (based on weather data from NatHERS in Richmond, lected to investigate the worst case scenario, and used to NSW and Darwin, NT) orientation, spatial arrangement determine the influence of Murcutt’s environmental de- and materiality, aiming to understand Murcutt’s archi- sign principles on the comfort conditions of the house. tectural design principles and how they respond to the Murcutt’s profound understanding of the site (its land- specific site contexts; then, a quantitative analysis was scape, views and climate conditions), led him to design a conducted by computer aided modelling (in Autodesk’s house whose main function was to provide shelter, while Ecotect, Radiance and EDSL TAS), to comprehend the allowing its internal spaces to be adjusted according to luminous and thermal environments of key spaces (i.e. their inhabitants needs. During summer, he considered living rooms and bedrooms). the heavy rains and high temperatures, which conse- Murcutt’s understanding of the Australian climate and quently would induce significant level of humidity; landscape contributes to the development of several key Murcutt also recognised that winter was mild and solar design principles, which he skilfully applies and readapts access would be his main concern. Murcutt’s in-depth in each project. Among his basic design principles, knowledge of the site’s climate, seemed to have led him building orientation (facing north) is essential, as it de- instinctively to overlay the traditional elongated wool- fines two fundamental design aspects: access to sunlight shed, with the lean aboriginal bark shelter on stilts, as a and prevailing winds. Additionally, Murcutt closely stud- new, reinterpreted building typology (Fig. 4); one which ies the site’s geomorphology and views, (Fig. 1) in order once raised off the ground ‘…also enhances airflow and to make an informed decision on the building’s setting. ventilation’ (Beck and Copper, [1]). Once these key aspects were defined, Murcutt studied As Fig. 4 above illustrates, the final design is composed the rainfall and solar angles to design the roofing and by two symmetrical modular wings, (one north oriented, overhangs shape and dimensions. In his buildings, he the other facing south) connected through a central favours slim spaces with a standard height (commonly corridor that acts as a rain gutter; both modules are 2.10 m.) and permeable, lightweight building skins based staggered and raised from the ground on wooden stilts; on vernacular architecture and aboriginal traditional the roof shape and overhang’s responds to the solar alti- shelters (Fig. 2); these spaces are then complemented by tude (84.8°) in summer solstice at noon, in order to pre- the reinterpreted building elements, (i.e. verandahs, vent direct solar ingress into the interior. According to clerestory windows, glazing louvres and blinds) whose Murcutt, designing two separate wings decreased the form, function and materiality are intended to act as the project’s scale and if relocation is needed, disassembly catalysts for Murcutt’s responsive architecture. will be possible; in addition, he “wanted the quality of living to be close to the edge, and to enjoy the landscape Spatial delight in the Marie-Short house views” [1]. This link between the inside and outside is In 1975, Murcutt was commissioned to design the maintained throughout the building, by introducing Marie-Short house located in farmland near the coast of openings on both main facades with glazed louvres and Lecaro et al. Future Cities and Environment (2017) 3:3 Page 3 of 18 Fig. 1 Left: Orientation as a basic design principle, allows the project to benefit from sunlight and prevailing winds. Right: Site analysis based on Glenn Murcutt’s sketches. Heath [8] blinds, providing the inhabitants the control of the Murcutt was seemingly conscious of the environmental amount of daylight and fresh air entering the building. implications of this alteration. When examining the The northern wing (facing the sun), contains the luminous environment of each wing, (while overlapping house’s main living spaces (i.e. main bedroom, dining the sun path diagram) as Fig. 6 illustrates, Murcutt room and kitchen) whereas, the southern wing contains intentionally arranged the spaces, so that the northern the secondary bedrooms and a more secluded living (and public) wing received sunlight throughout the year. room. The central corridor is vital, as the pivot-hinged doors connect the main social spaces, while improving Daylight assessment of the Marie-Short house the conditions for cross ventilation. At the end of the In order to assess the daylighting performance of this corridor, both wings are buffered by verandahs, which house during summer, the house’s main spaces, (i.e. living act as shading devices. rooms and bedrooms) were analysed under an overcast When analysing the house’s current layout, it shows sky condition, on 1st March (warmest day), with all the that Murcutt positioned the main bedroom to the east, blinds fully opened. In this study, both the daylight factor waking up the building occupants by the morning sun and daylight illuminance were analysed and compared. and exposing the space to the morning heat gains as As shown in Fig. 7, the northern living room (NLR) well. However, as shown in Fig. 5, the original layout achieved an average daylight factor of 5% and an illu- was conceived differently, as two wings with distinctive minance level greater than 650 lux towards the exterior uses, (i.e. north wing contained social spaces, while the and lower than 150 lux near the back wall. Whilst the southern wing, the bedrooms) and therefore, with differ- relatively high daylight factors (between 5% to 9%) indi- ent spatial needs and environmental performances. cate that there is no need for artificial lighting for most The current northern wing, was designed to receive time of the year, and the illuminance levels exceed sunlight and prevailing winds, whereas the southern wing CIBSE’s Code for Interior Lighting [5] recommendations. was intended as a relaxing area thus, sheltered from direct However, the high illuminance contrast between the ex- exposure to sunlight and heat gains. After the extension, terior and the back wall, could potentially cause visual Fig. 2 Left and middle: Australian aboriginal bark shelters on stilts (off the ground). From Lee [12]. Right: Australian veranda. From, West End Cottage [11] Lecaro et al. Future Cities and Environment (2017) 3:3 Page 4 of 18 Fig. 3 Left: Traditional Australian woolshed. Murray Johnson. Right: Marie-Short House (1980). Richard Powers discomfort (i.e. glare) unless the internal blinds are 4.5%, whereas the illuminance levels rapidly increase drawn. from 150 lux in the centre, to 750 lux towards the Given the difference in the orientation of the southern windows. Although artificial lighting was needed as a living room (SLR) and the North Living Room (NLR), supplementary light source, the risk of visual discomfort different daylighting performance were expected. As might occur, but this The southern bedroom (SB), was shown in Fig. 7, surprising results were obtained for the strategically positioned by Murcutt to receive more daylight simulations, while the average daylight factor direct sunlight (and heat gains) throughout the year a was of 9%, the illuminance levels on the interior sur- (see Fig. 8). The average daylight factor was 9% (indicat- faces, ranged between 250 and 750 lux. Despite daylight ing no artificial lighting is needed), while the illuminance is more uniformly distributed when compared to NLR, levels ranged similarly to the NB, (i.e. between 150–750 (as it receives both indirect light from the exterior, and lux) suggesting internal blinds are needed to reduce the direct light from the skylight Murcutt designed for this high illuminance contrast and reduce the risk of glare. space), the light levels indicate the potential risk of visual discomfort too. Thermal assessment of the Marie-Short house The bedroom areas, given their use and arrangement To assess the thermal conditions in the selected spaces were expected to perform differently from the living (during summer), a model of the house was built in EDSL rooms previously assessed. As shown in Fig. 8, the aver- TAS, distributing each space as a separate thermal zone age daylight factor for the northern bedroom (NB) was (Fig. 9), and analysing the connection between their Fig. 4 Top: Current layout of the house, by Ozetecture (2013). Bottom: Sun, wind and rainfall analysis in the MSH Lecaro et al. Future Cities and Environment (2017) 3:3 Page 5 of 18 Fig. 5 Original layout (1975) and current layout after renovation (1980). Layouts by Murcutt [13] resultant temperatures in relation to their openings, no natural ventilation, case 2 as the worst possible sce- building materials and adjacent buffer zones (i.e. ve- nario with internal heat gains but without natural ventila- randahs). These thermal simulations were performed tion; cases 3 and 4 represented the best possible scenarios, from day 355 until day 80, corresponding to the and natural ventilation was introduced initially by having Australian summer time. a 50% effective aperture, and then a 95% effective aperture The assessment considered four possible cases (Table 1), to the openings, so that a clear understanding of the all having a constant natural infiltration rate of 0,25 ACH impact of natural ventilation on thermal comfort can be and shading as designed, but varying in the levels of in- obtained. ternal heat gains and natural ventilation rates. Case 1 was The following assumptions were considered for the set up as a base example with no internal heat gains and simulations: Fig. 6 Time and spatial arrangement. Sunpath analysis during summer solstice, equinox and winter solstice Lecaro et al. Future Cities and Environment (2017) 3:3 Page 6 of 18 Fig. 7 Daylight performance comparison between living rooms. DF (%) and Illuminance assessment in ECOTECT and Radiance Fig. 8 Daylight performance comparison between bedrooms. Daylight Factor (%) and Illuminance assessment in ECOTECT and Radiance Lecaro et al. Future Cities and Environment (2017) 3:3 Page 7 of 18 Fig. 9 Thermal zoning of key spaces for simulation in the Marie-Short house. Thermal assessment in EDSL Tas Weather: Energy Plus weather data for Brisbane, occupied and set to start opening when the Queensland. temperature reached 25 °C and to be fully opened Comfort range: during summer it was assumed to at 28 °C. be between 25 °C to 28 °C.  All the cases included shading from the blinds and Calendar: summer period was assumed to be from verandahs. the 21st of December until the 22nd of March. Internal Gains: the following values were assumed: Similar to the analytical methodology adopted in the ○ Three people occupying the house, whose heat daylighting performance analysis, thermal analysis re- gains were assumed to be 120 W per person, sults were compared in each thermal zone with similar 75 W sensible and 45 W latent. activities, with an aim to exam the correlations among ○ The occupancy schedule was set assuming a them. The results were presented as a percentage of weekly work schedule, were occupancy is highest time when the resultant interior temperatures were during sleep time and falls during daytime, ranged between 25 °C and 30 °C. experiencing peaks during early morning (6-9 am), As Fig. 10 shows, both living rooms present different lunch (12-2 pm) and evenings (5 pm onwards). thermal performances. It is important to emphasize, that Lighting: compact low-energy florescent bulbs with while both zones have a similar area, the heat gains vary a 25 W thermal load per light bulb, with a total load greatly, as the northern living room includes the heat of 9 W/m gains from kitchen’s appliances. Equipment and appliance gains: equipment’s considered were a hob, a washing machine, a  Case 1: in both zones, only 45% of the occupied dishwasher and a fridge, all with a total load of hours are above the comfort range. 27 W/m .  Case 2: the addition of internal heat gains while the Infiltration rate: was considered to be 0.25 ACH in envelope remains closed, (without any ventilation) all zones. led to a significant increase in the number of hours Ventilation: all openings have the same opening outside the comfort range in both zones. In the patternduringthe periodswhenthe house was NLR, over 48% of the occupied hours are outside the comfort range, while for the SLR, over 84% of the occupied hours are outside the comfort range, Table 1 Summary of thermal cases examined indicating that the building envelope and shading Presence Presence Presence Presence devices alone are not adequate to offer desirable (Yes/No) (Yes/No) (Yes/No) (Yes/No) thermal comfort in this building. Internal heat gains NO YES YES YES Case 3: 50% of effective aperture in doors and Natural ventilation NO NO YES (50%) YES (95%) windows significantly increased the number of hours Case 1 2 3 4 within the comfort range for both zones, proving Lecaro et al. Future Cities and Environment (2017) 3:3 Page 8 of 18 Fig. 10 Thermal performance comparison in living rooms. Thermal assessment in EDSL TAS that natural ventilation work as intended. The the exposed facades provided by the verandahs, simulation results also show that for over 60% of the However 35% of the occupied hours are still outside time, the resultant temperatures are within the the comfort range. comfort range.  Case 2: the results indicated that the addition of Case 4: 95% aperture in openings did not internal heat gains (while the envelope is closed), do significantly improve what was achieved in the not significantly affect the number of hours the previous case and comfort condition is achieved for bedrooms are within the comfort range (over 50%). over 60% of the occupied hours, indicating that a The spatial arrangement of these spaces within the partial effective aperture of the openings (in Case 3) house is the key to attain the thermal comfort levels. is sufficient to cool down the internal temperatures.  Case 3: 50% of aperture in doors and windows increased the number of hours (above 70%) for the Thermal performance in both bedrooms shows a com- resultant temperatures fall within the comfort range parable trends as shown in Fig. 11. in the bedrooms, indicating that natural ventilation improves the thermal comfort. Case 1: in both zones, the percentage of achieving  Case 4: A 95% of aperture in openings, slightly comfort levels without any ventilation present is increased the number (above 75%) of hours for the over 65% of the hours; this is due to the shading on resultant temperatures fall within the comfort range, Lecaro et al. Future Cities and Environment (2017) 3:3 Page 9 of 18 Fig. 11 Thermal performance comparison in bedrooms. Thermal assessment in EDSL TAS showing that higher effective aperture is essential to the interior spaces were clearly defined between served improve the thermal comfort of these spaces. spaces (i.e. bedrooms), positioned to the SW and serving spaces (i.e. living space) to the NE, intending to position Spatial delight in the Ball-Eastaway house the main spaces in contact with the exterior. Completed in 1983, the Ball-Eastaway house is located The section derived from a thoughtful site analysis, at a remote bush land in Glenorie, NSW (33.6° S) and it when the site’s high rainfall and surrounding trees were was designed as a retreat and workspace for its artist considered, Murcutt recognised that conventional gut- owners. Murcutt intentionally positioned the house over ters and pipes would block, therefore a vaulted, corru- a sandstone bed, and changed his distinctive preference gated iron roof with broad gutters was his response for north orientation to exploit the site’s views and to (Fig. 13). Additionally, he favoured a light-weighted steel create a more peaceful atmosphere (Fig. 12). structure, (minimizing the use of timber) and corrugated As suggested by Farrelly [6], this house’s configuration iron exteriors, contrasting with the natural setting and responds to the sandstone’s bed shape, which offered the softer and warmer interior. Murcutt the opportunity to lift the house off the ground According to NatHERS (2014), the site experiences a on steel stilts (Fig. 12), protecting the building from seasonal climate with temperature range between 39,5 °C wildfires while providing a less invasive building process; (January) and 0 °C (August) and a monthly mean rainfall Lecaro et al. Future Cities and Environment (2017) 3:3 Page 10 of 18 Fig. 12 Left: Exterior view by Max Dupain. Source: Levene and Marquez [10]. Right: Plan and spatial arrangement ranging from 122 mm (February), to 28,5 mm (July); Daylight assessment of the Ball-Eastaway house therefore the building’s orientation and envelope are es- To assess the daylighting performance of the house’s sential to cope with the site’s climatic conditions. main spaces, (i.e. living room and bedroom) and to en- When the building’s orientation is analysed in relation sure that the spaces were adequately day-lit, a target to the sun path diagram, Murcutt’s intention of favour- daylight factor of 2%, based on BSI [3] standard guide- ing the site’s views over a valuable north orientation is lines, was chosen to analyse their daylighting perform- evident. As Fig. 13 shows, the house’s orientation ex- ance under overcast sky conditions. As shown in Fig. 14, posed the public areas to partial sunlight ingress in the the average daylight factor in the main spaces was above morning, while underexposed the private ones at the 5%, indicating that all spaces are well-day lit and no sup- same time. According to NatHERS (2014), the optimum plementary lighting from artificial sources is needed as orientation would convey in better solar access (and heat CIBSE [4] established. gains) during winter, while providing a better opportun- The uniformity ratios and light journey achieved (Fig. 14) ity to exploit the site’s prevailing winds during summer. in the internal spaces, showed that Murcutt designed and When the house’s section is overlapped with the solar positioned the openings intentionally to create a dynamic, angles during equinox and solstices at noon, it is clear that yet relaxing atmosphere. Despite the house’s orientation is the roof was not intended to respond to the sun (Fig. 13), not optimum, Murcutt was able to make a clear transition reinforcing the argument that orientation was not a prior- between the living space and the bedrooms. The most dra- ity here; nevertheless, the roof still provides shelter from matic variation can be perceived in the main entrance, the summer sun at noon and the associated heat gains, where the daylight factor drastically lowered providing vis- while admitting partial solar access during winter. As a ual adaptation to the inhabitants through the corridor. free-running building, the house was designed to be To investigate the illuminance distribution within the cooled by natural ventilation, hence Murcutt raised it house’s most occupied space (i.e. living room), daylight off the ground intending to improve cross-ventilation illuminance was assessed at noon under sunny sky and reduce internal temperature during summertime. (Equinox) and overcast skies conditions, to have a Fig. 13 Left: Ball-Eastaway’s orientation vs. sunpath during winter and summer solstice and optimum orientation. Source: NatHERS (2014) Right: Section vs. solar access at noon during summer solstice, equinox and winter solstice Lecaro et al. Future Cities and Environment (2017) 3:3 Page 11 of 18 Fig. 14 DF plot and section, uniformity ratios and light journey in the Ball-Eastaway house broader understanding of its performance. The results blinds or external architectural features were included, a were compared to CIBSE [4] 300 lux recommendation. more visually comfortable space could be provided. As Fig. 15 illustrates, the high illumination levels (+680 lux average without internal blinds) present dur- Thermal performance and spatial delight in the ing sunny sky conditions in Equinox, indicates that while Ball-Eastaway house the space is well day-lit, an over-lit environment or vis- Evaluating the thermal environment of the house was essential ual fatigue might be experienced; under overcast sky to have a full understanding of the building’s performance and conditions, the average illuminance levels significantly its impact on comfort, especially when Murcutt’sprojectsare decreases to 280 lux, indicating adequate daylight illu- designed as free-running buildings, with operable envelopes minance is provided for visual perception; However, in designed to adapt to the climatic challenges. As Kallenbach [9] both cases, the high illuminance levels achieved towards echoed Murcutt’swords ‘[just as] we layer our clothing…our the opening indicate that, the use of blinds or operable buildings should equally respond to their climates.’ shading devices is needed for improving the luminous Since this house’s orientation and spatial arrangement environment. pointed to an unlikely positive thermal performance, a To assess the luminous intensity, the brightness con- model of the house was built in EDSL TAS, distributing trast ratio was used to evaluate whether the house pro- each space as a separate thermal zone (Fig. 17); simula- vides visual comfort for its occupants in the living room. tions were performed aiming to have an overall idea of Although the sky conditions on site are mostly overcast, the annual thermal performance in key spaces, neverthe- the luminance mapping was performed under both, less, analysing winter’s performance was essential and sunny (Equinox) and overcast sky conditions, so that a the chimney’s heat transfers were considered. more realistic luminous environment could be evaluated. The assessment considered three possible cases (Fig. 17), Murcutt designed the corridor as an exposition area all having a constant natural infiltration rate of 0,50, shad- for paintings, offering the best target for brightness con- ing as designed and varying in the levels of internal heat trast assessment. As Fig. 16 shows, the visual target con- gains and natural ventilation rates. Case 1 was set up as a sidered does not suffer from major visual discomfort; base example with no heat gains and no natural ventila- however, as the results demonstrate, if the target is tion; Case 2 as summer’s scenario with natural ventilation shifted towards the dining room, the luminance contrast and heat gains; Case 3 represented winters’ scenario and might significantly change, implying that under these all internal heat gains were included and natural ventila- sky conditions the inhabitants may suffer from glare. If tion was set to occur only if the resultant temperatures Fig. 15 Illuminance (lux) plots at noon under sunny sky (Equinox) and overcast sky conditions Lecaro et al. Future Cities and Environment (2017) 3:3 Page 12 of 18 Fig. 16 Luminance (cd/m2) assessment at noon under sunny sky (Equinox) and overcast sky conditions surpassed the established comfortable temperature Thermal analysis results were compared between both range. Aperture variation in openings was considered thermal zones, comparing seasonal thermal performance to recognise the influence of natural ventilation on vs. average resultant temperatures to examine the correla- thermal comfort. tions. Results wereshown as apercentageoftimewhenthe In order to define a comfort zone, monthly average tem- resultant interior temperature ranged between 19 °C to 23 ° peratures were used as a base to calculate the optimal Cinwinter, and22°Cto 27°Cinsummer. As Fig. 18 temperature for comfort (i.e. T )inRichmond, NSW, shows, both spaces share a similar thermal performance; comf based on the Adaptive Model by Nicol et al. however, during winter, the living room’s performance im- The following assumptions were considered for the proved while the bedroom’s performance becomes worse. simulations: The following conclusions were drawn from this analysis: Weather: Energy Plus weather data for Richmond,  Case 1: Annually, 20% of the occupied time in the New South Wales. house falls within the comfort zone, (except during Comfort range: winter between 19 °C to 23 °C, and winter when performance falls to 15%), inferring 22 °C to 27 °C during summertime. heat gains are essential to improve the thermal Calendar: Annual performance. Internal Gains:  Case 2: The thermal comfort in the internal spaces is ○ Occupancy: two adults with heat gains assumed within the comfort range for 25% of the time; despite to be of 180 W (sensible) and 100 W (latent). heat gains improved the percentage of time within the ○ The occupancy schedule was set for 24 hours. comport range, resultant temperature was 17 °C Lighting: compact low-energy florescent bulbs with (below comfort); in summer, natural ventilation can a total load of 2,5 W/m help improve the thermal environment as the Equipment gains: hob, a washing machine, a dishwasher predicted resultant temperature reached 22 °C. and a fridge, all with a total load of 25 W/m .  Case 3: represented the best scenario during winter Chimney sensible gains of with a total load of 40 W/m . for the living room, while unexpectedly the worst Ventilation: during occupancy periods all openings for the bedrooms; the chimney’s heat gains seem to had the same opening pattern; starting to open have a significant impact on the living room’s when the temperature reached 19 °C and fully thermal performance, but seemingly the envelope’s opened at 27 °C. airtightness is not enough, as heat gains from the Fig. 17 Left: Thermal assessment and zoning of key spaces in the Ball-Eastaway house. Thermal assessment in EDSL Tas. Right: Summary of thermal cases examined Lecaro et al. Future Cities and Environment (2017) 3:3 Page 13 of 18 Fig. 18 Seasonal thermal performance of main spaces vs. average exterior and resultant temperatures chimney seemingly do not reach the bedrooms. while arranging the spaces responding to aboriginal trad- During summer there was no perceptible ition, with the adult’s room positioned to the West, where improvement, indicating that natural ventilation by thesun sets, whilethe children’s bedrooms are located to itself is not enough to dissipate the internal heat the East, where the sun rises symbolizing new life. In this gains. Annually both spaces performed thermally at project, Murcutt converged and materialized his life learn- an average of 30% of the occupied time. ings on Thoreau’s philosophies, with the lessons learnt from vernacular architecture and aboriginal way of life, Fromo- Spatial delight in the Marika-Alderton house not [7]. The Marika-Alderton house is positioned by the seaside in The house’s section was conceived to fully respond to the Eastern Arnhem, NT (12.5° S) and was completed in 1994. site’s tropical climate, (i.e. harsh sunlight, high tempera- According to Beck and Copper [1], the house was designed tures, humidity levels and occasional cyclones) while pro- for an aboriginal family intending to create a dwelling that viding visual connection with the exterior; Murcutt followed native traditions, while providing shelter from cli- conceived a slim, symmetrical section (Fig. 19) raised off mate. Murcutt oriented the house facing north (Fig. 19), the ground on steel pillars to improve the effect of natural Fig. 19 Left: Marika-Alderton house. Photography by: Reiner Blunck. Source: El Croquis (2013). Right: Spatial arrangement and section vs. solar angles Lecaro et al. Future Cities and Environment (2017) 3:3 Page 14 of 18 ventilation, while the roof’s long overhangs protect the in- skies conditions; results were compared to CIBSE [4] terior from sun and rain. An operable and permeable enve- 300 lux recommendation. lope, (composed by slatted shutters, doors, tilting plywood As illustrated in Fig. 22, under sunny sky conditions panels and sun breakers) ensures a constant flow of fresh during Equinox, shading devices completely protect air, while the sun breakers provide shading to all bedrooms surfaces from direct sunlight, yet the high light levels from low-angled southern sun. (+600 lux average) indicate that even if the space is well When the envelope and structure’s materiality is ob- day-lit, visual fatigue may be experienced, suggesting served, the pragmatic and unpretentious intentions of that if the operable openings were closed, this condition Murcutt is clear. By using modest building materials such might considerably improve; however, under overcast as steel, timber, plywood and corrugated iron, it is possible sky conditions, the illuminance levels achieved between to orchestrate a space that adapts accordingly to climate. 250 – 300 lux in average, indicating desirable luminous According to BOM [2], the site experiences constant environment with good level ofvisual acuity. high temperatures (18 °C to 35 °C), humidity, rainfall, According to the results of the brightness contrast solar radiation levels and occasional cyclonic winds, thus analysis (Fig. 23), the brightness contrast ratio between while encouraging natural ventilation, blocking undesired the visual tasks and their surroundings proved that ex- sunlight is required. As Fig. 20 shows, the house’sorienta- periencing visual discomfort is unlikely to occur. The tion as designed is very close to the optimum orientation. careful selection of building materials with relatively low Murcutt merged the outside and inside, with an aim to reflectance (i.e. mostly wood in the interior), decreased cool down the interior through natural ventilation and the chance of experiencing visual discomfort. Neverthe- shading; nevertheless, its permanent contact with the ex- less, this study was performed considering all shutters terior makes the building dependent on exterior tempera- remained opened (as worst case scenario); if they were tures to achieve comfort, hence an increase in wind speed closed, the risk of visual discomfort would be signifi- is necessary conscious of this, Murcutt included in the cantly reduced. roof several Windworkers designed to increase air flow within the house, encouraging natural ventilation and the Thermal performance and spatial delight in the extraction of heat trapped in the roof (Fig. 20). Marika-Alderton house The constant permeable nature of the house was consid- ered, as it is dependent on the exterior thermal environ- Daylight assessment of the Marika-Alderton ment and wind to cool down the interior. Additionally, house the shallow envelope (built on elements with low ther- Following the methodology described in the above case mal properties), and warm air been constantly pushed study, the daylighting performance of the house’s main into the house were taken into account. spaces, was investigated under overcast sky conditions. To assess the thermal conditions, a model of the house As Fig. 21 shows, the average daylight factor in the main was built in EDSL TAS (Fig. 24), distributing each space spaces ranged from 3% to 5%, indicating that most of as a separate thermal zone. The simulations were the spaces are well-day lit and artificial lighting is re- performed aiming to have an overall idea of the annual quired for most of the time. Additionally, the light jour- performance of the main living spaces and to provide ney graph indicates a continuous variation in daylight, evidence on the effect that solar radiation, natural venti- ranging from a vivid atmosphere in serving spaces, to a lation and internal heat gains had on the resultant calmer one in the bedrooms. temperatures annually. In order to have more realistic The daylight illuminance was assessed in the living results, the Windworkers’‘Venturi’ effect was simulated space, at noon under sunny sky (Equinox) and overcast by adding opaque openings to the roof. Fig. 20 Left: Spatial arrangement and sunpath during winter and summer solstice; Optimum orientation. Source: NatHERS and Autodesk Ecotect’s weather tool (2014). Right: air movement and cross-ventilation produced by Windworkers Lecaro et al. Future Cities and Environment (2017) 3:3 Page 15 of 18 Fig. 21 DF plot and section, uniformity ratios and light journey in the Marika-Alderton house. Source: Authors The assessment considered three possible cases (Fig. 24),  Ventilation: opening schedule is based on all having as constants: shading, natural ventilation (vary- occupancy, partial natural ventilation is allowed ing accordingly to each case) and infiltration rate 0,50; 24 hours a day. heat gains were the only variants. Case 1 was set as a base example with partial natural ventilation and no heat gains; Thermal analysis results were compared between both case 2 represented the worse scenario, as heat gains were zones, relating seasonal thermal performance vs. average included; case 3 was designed as the best possible sce- resultant temperatures. Results are shown as a percent- nario, as natural ventilation was increased to have a stron- age of time when the resultant interior temperature ger perspective on the influence natural ventilation had on ranged between 23 °C to 28 °C; yet the consequences of thermal comfort. the house being an open space have to be considered. Setting a comfort zone for this analysis, followed the As Fig. 25 shows, both spaces shared a similar thermal same principles, equations and guidelines described in performance; annually none of the spaces reached a 30% teh above case study, based on the optimal temperature of time within the comfort range, having significantly high for comfort (i.e. T ) in Darwin (NT), and based on resultant temperatures fluctuating between 27 °C to 35 °C. comf the Adaptive Model by Nicol et al. The following conclusions were drawn from the analysis: The following assumptions were considered for these simulations:  Case 1: 20% of the occupied hours in a year are within the comfort range (without any heat gains). Weather: Energy Plus weather data for Darwin, NT. During winter the thermal performance fell with Comfort range: assumed to be between 23 °C to 28 °C 16% of the occupied hours falling within the Calendar: Annual comfort zone. Internal Gains:  Case 2: Presented an insignificant improvement ○ Occupancy: 2 adults and 4 children; heat gains when compared to Case 1; only a 3% increase of the assumed 450 W (sensible) and 250 W (latent). time within the comfort zone was experienced when ○ The occupancy schedule was set assuming a natural ventilation was introduced; overheating 24 hours. could be experienced and extra cooling is needed. Lighting: compact low-energy florescent bulbs with  Case 3: The comfort range slightly increased to 25% a total load of 1,5 W/m when twice the air flow was introduced, still the Equipment gains: equipment’s considered were a building is unable to rapidly exhaust warm air hob and a fridge, with a total load of 25 W/m . trapped under the roof, leading to overheating. Fig. 22 Illuminance (lux) plots at noon under sunny sky (Equinox) and overcast sky conditions Lecaro et al. Future Cities and Environment (2017) 3:3 Page 16 of 18 Fig. 23 Luminance (cd/m2) assessment at noon under sunny sky (Equinox) and overcast sky conditions Overall, the thermal performance of both spaces is poor, depth contextual knowledge is overlaid with his main only 30% of the occupied hours in a year are within the environmental design strategies, (i.e. orientation, nar- comfort range, demonstrating it potentially needs mech- row plans with climate-responsive sections, natural anical cooling; however, the thermal conditions could po- ventilation, shading and light-weighted operable skins) tentially be improved and moderated by the occupants’ an architecture that adapts to the local climate and site control of the building’s operable envelope. conditions is born. When the luminous environments in the three selected Conclusion buildings were analysed, they proved to be mostly well Through an in-depth analysis of each house, supported day-lit, nevertheless throughout all projects assessed, in by the factual evidence gathered from qualitative and order to improve visual comfort, shading devices (such as quantitative analysis, the authors have attained a holistic blinds, shutters or sun breakers) need to be constantly understanding of Murcutt’s architectural achievements, deployed. However, Murcutt’s skilful way of handling day- the reasoning behind his design approach and building light produced subtle light journeys in the houses, which solutions. Moreover, the authors have outlined the sig- offers variation in intensity depending on the spatial func- nificant impact that Murcutt’s design intents have on the tion and intended atmosphere, ranging from vibrant light visual and thermal comfort of his buildings. in public spaces, to soothing light in private ones. From a qualitative perspective, not only were Murcutt’s For the thermal environments in his houses, the thermal design intentions revealed, but also, the intrinsic connec- analysis revealed occasional thermal discomfort. Consider- tion he proposed between the manmade space and nature ing the houses’ envelopes as designed, the results showed were presented. Through simple forms and humble mate- that in the Ball-Eastaway house, the thermal performance rials, Murcutt merges his buildings with nature, not im- of the main spaces fell below an annual average of 30% of plying the superiority of one over the other, but through the occupied time within the comfort range, suggesting unity, his architecture constantly reminds us the signifi- that improving the envelope’s insulation and airtightness, cance of nature. combined with extra heating (for winter) could potentially Detailed site-specific climate analysis including the solar improve the house’s thermal comfort. In the Marika- trajectory, prevailing winds, rainfall and landscape, is Alderton house, which presented an annual average of Murcutt’s essential first step in dealing with a design chal- 25% of the time within the comfort range, showing that lenges. When all these factors combine, nature seems to even when the Windworkers was used to increase the air speak and guide him to define forms and spaces that movement, the main spaces still experienced overheating are translated into climate responsive, potentially free- which is caused by the fact that the building’s envelope running vernacular inspired architecture. Once this in- was designed to be light-weight and the roof is not Fig. 24 Left: Thermal assessment and zoning of key spaces in the Marika-Alderton house. Thermal assessment in EDSL Tas. Right: Summary of thermal cases examined Lecaro et al. Future Cities and Environment (2017) 3:3 Page 17 of 18 Zone Frequency (%) of hours in comfort zone vs. seasonal average resultant temperatures. Fig. 25 Seasonal thermal performance of main spaces vs. average exterior and resultant temperatures insulated. However, occupants’ active control of the oper- changes and adapts to the climate and its inhabitants able building envelopes might potentially help reduce cer- needs. tain degree of overheating in summer. The spatial and environmental delight in Murcutt’s In the Marie Short house, Murcutt’s environmen- buildings lies in this delicate relationship between tal design strategies, (i.e. orientation, natural ventila- providing an enriching spatial experience (through a tion, shading and designing a light weighted constant connection with nature), and at the same time building, raised off the ground on stilts) created a offering desirable comfort conditions. Through his low energy building, which constantly interacts with pragmatism, Murcutt designed buildings responding to theoutside,and offers theinhabitants theopportun- the site conditions and climate. Through the balance ity to dictate how to operate and adapt their spaces. between man and nature, Murcutt’s buildings are vivid, Undoubtedly as the results demonstrated, in order healthy and delightful, but more importantly, they are to maximise thermal comfort the key living spaces designed to be operable and constantly influenced by are dependent on natural ventilation, as the shading the external conditions, in order to allow the inhabi- alone will not significantly decrease the resultant tants to fully experience and control their space. temperatures. On the other hand, even though It is important to reflect that Murcutt designed these Murcutt provided the main facades with integrated environmental conscious buildings by utilising unpreten- blinds, the results have shown that if left opened, tious local materials and construction techniques. The the inhabitants will experience visual discomfort, in- constant connecting of his architecture with the natural dicating that even when Murcutt wanted to have a environment, and his unique application of reinterpreted constant connection with nature, reconsidering the vernacular elements such as verandahs, overhangs and opening sizes might help improve the visual comfort narrow spaces with permeable skins combined with and spatial delight of the house. Murcutt’s environmental design strategies has produced When the Marie-Short house is fully investigated and self-reliant, low energy consumption buildings. its performance assessed, Murcutt’s design excellence In the case of the Marie-Short house, its cleverness at and skilfulness are more significant than this building’s first glance is disguised as a modest woolshed. It stands apparent deficiencies. The Marie-Short house has to be lightly, quiet and unpretentious surrounded only by the analysed as a free-running building, which constantly Australian landscape. Through this humble design, Bedroom Living space Lecaro et al. Future Cities and Environment (2017) 3:3 Page 18 of 18 Murcutt transformed a seemingly artless woolshed, into 10. Levene RC, Márquez C (2012) Glenn Murcutt 1980–2012: Plumas de Metal - Feathers of Metal. El Croquis, Madrid a fascinating habitat, allowing its inhabitants to adjust 11. West End Cottage (2012) Verandahs and Sleep outs. http://westendcottage. the spaces accordingly to their needs. Just as Heath [8] blogspot.co.uk/2012/07/verandahs-and-sleepouts_20.html. Accessed 16 May described Murcutt’s work as a choreography, ‘designed 2014. 12. Lee D (2010) Aborigines People. http://warearthissue2010.blogspot.co.uk/ so it can literally be tuned like an instrument to respond 2010/09/aborigines-people.html. Accessed 30 Mar 2017. to seasonal cycles’, the Marie-Short house performed as 13. Murcutt G, The Marie Short House (2014) OZETECTURE. Available at: http:// it was designed to, as a free-running building. www.ozetecture.org/2012/marie-short-glenn-murcutt-house/. Accessed 17 May 2014. Murcutt’s spatial quality transcends from mere aes- thetics into workable, adaptable and pleasing spaces; through his buildings, Murcutt has revitalized (rather than imposing) the vernacular architecture principles and reapply them to create humble, yet site specific and innovative architecture. Abbreviations CIBSE: Chartered Institution of Building Services Engineers; EDSL: Environmental Design Solutions Limited; NatHERS: Nationwide House Energy Rating Scheme (Australia); NB: Northern bedroom; NLR: Northern living room; NT: Northern Territory Australia; SB: Southern bedroom; SLR: Southern living room Funding The author Mauricio Lecaro received a scholarship by the Republic of Ecuador through SENESCYT's scholarship program named "Convocatoria Abierta 2013 - Primera Fase". Authors’ contributions ML did the research, software analysis and initial draft of the paper. LR and BL provided guidance, reviewed and supervised all stages of this study. DJ reviewed and edited the material to generate this technical report. All authors read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Publisher’sNote Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Author details Gensler, Avenida Escazú, Torre Lexus, piso 7, San José 10203, Costa Rica. Department of Architecture and Built Environment Faculty of Engineering, University of Nottingham University Park, NG7 2RD, Nottingham, UK. Received: 19 August 2016 Accepted: 28 February 2017 References 1. Beck H, Cooper J (2002) Glenn Murcutt: A Singular Architectural Practice. Edition. Images Publication Group, Melbourne. 2. Bureau of Meteorology, BOM (2014) Climate of New South Wales. www. bom.gov.au/lam/climate/levelthree/ausclim/ausclimnsw.htm. Accessed 23 Aug 2014. 3. British Standards Institution, BSI (2008) Lighting for buildings. Code of Submit your manuscript to a practice for daylighting. B S I Standards, London. journal and benefi t from: 4. Chartered Institution of Building Services Engineers, CIBSE (1994) Code for interior lighting. Chartered Institution of Building Services Engineers, 7 Convenient online submission London 7 Rigorous peer review 5. CIBSE (2002) Code for Lighting, 1st edn. Butterworth-Heinemann, London 6. Farrelly EM (2002) Three houses: Glenn Murcutt. Phaidon, London 7 Immediate publication on acceptance 7. Fromonot F (2003) Glenn Murcutt: Buildings and Projects 1962–2003, 2nd 7 Open access: articles freely available online edn. Rev Sub edn. Thames & Hudson, London and New York. 7 High visibility within the fi eld 8. Heath K (2009) Vernacular Architecture and Regional Design, 1st edn. 7 Retaining the copyright to your article Routledge, London 9. Kallenbach L (2002) Architect Profile: Glenn Murcutt. Available at: http:// www.motherearthliving.com/green-living/nh-natural-home-journal2. Submit your next manuscript at 7 springeropen.com aspx#axzz3BRxfGvyC. Accessed 16 May 2014.

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Future Cities and EnvironmentSpringer Journals

Published: Apr 4, 2017

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