Building Design

The project master plan provides a new model of multi residential design for a coastal location. It essentially rejects a uniform monolithic approach to the design layout in favour of a more strategically placed diverse set of liner forms with varying heights. It was evident at the time that conventional practices for public and private housing were under scrutiny from the community. This provided climatic as well as socio-cultural generators for the master plan and unit design which then lead to a number of innovative features. The notable features include the three storey walk up units which are located at the southern part of the site, the use of open spaces for car and community use and the high quality semi private external space attached to each unit. The road and pedestrian routes are aligned to the prevailing breeze and also create breezeways through the site. The layout of the units channel and funnel this wind effect rather than blocking and creating still air pockets. The main design principle is to allow sufficient space between buildings to allow air pressure to pull air from higher down into the units and public spaces. The heat sink effect of hard surfaces is minimised with the use of covered car parking areas and semi private spaces. The view though the site shows the way the building massing on the site provides access to summer sea breezes with the access roads being treated in an informal manner. The conventional road design essentially defines certain public/private boundaries through road materials and surfaces elements such as a mowing strip. Concrete curbing and tarmac is avoided in favour of a range of surface materials that define and mark special territories. This allows the roads to become both courtyards for social activity and areas for climate moderation as wells as functional spaces for vehicle access and service. The key ESD principle at work here is to place as much attention to the design of the external spaces in the master planning as the internal space. In this way a clear relation between inside and out can be achieved. The design evolved from a number of forums between stakeholders including Clare Design, the Sunshine Coast Regional Housing Council and staff and students of the Department of Architecture, The University of Queensland. The outcomes enhanced the stakeholders understanding of the environmental issues involved and enabled the integration of both the natural and social environments (Keniger, M. 1999). This is manifested in the site planning. As previously discussed, the site for the project consisted of two adjacent blocks, one owned by a private developer and one in public ownership. This afforded the challenge to provide an integration of the social, environmental and visual melieu. In physical terms this means equal opportunity to environmental access for thermal comfort and amenity, as well as consistency in form and space between the two developments.

Unit Design

The unit design responds to key climate responsive strategies for cooling and heating in southern Queensland. These are found in the bioclimatic chart (Olgay 1962, Hyde R.A., 2000). A significant feature of the unit design is the response to orientation. The micro climate of this area favours a north eastern orientation since the buildings can be aligned to allow environmental access to early morning sun in winter and summer cooling breezes. Also it is advisable to reduce access on the western orientation due to cool winds in winter and evening high solar loads in summer. The form that results from this microclimate condition is to place living spaces with access to the north. The design of the units utilise these strategies as shown in Table 1:

tabel 1

When designing buildings in urban locations, constraints placed on the design due to the conditions of the site often means that options are reduced. For example in higher density environments, microclimate control can be lost though wind shadows. Deep plan buildings are often used for higher occupancy densities, which in turn directs the designer to select larger floor plates, and a less climate sensitive building. The consequence is a reliance on plant and equipment. As an alternative with an environmental design approach there is a deliberate emphasis on working with the microclimate, envelope and building fabric to reduce mechanical plant requirements and ensure a passively controlled building. These latter strategies have been adopted in the Cotton Tree project and are shown in Table 1. The external appearance of the buildings follows a lightweight timber and tin aesthetic, characteristic of the regional architecture. Interestingly, the buildings are a mixture of heavy and lightweight materials and systems: the low-rise buildings are timber with suspended timber floors, and masonry cross walls, whilst the three story units are load bearing masonry walls with concrete slabs, and lightweight external veneer systems. The buildings use corrugated iron cladding to the first and second floor, with fibre cement for the top floors. Bulk insulation and radiant barriers are used in the roofs, with only radiant barriers and air cavities used as thermal protection in the walls. The materials and detailing demonstrate a life cycle perspective as well as a clear tectonic in the architecture. The honest expression of materials and the differentiation in the facade respect the need for a robust durable material at the ground plane. The composite wall construction optimises the low embodied energy potential, while reducing heat gain and loss. Minimal corrective maintenance is required to the envelope. The essence of the project resides in the detailing which can be seen in the section through the public housing. Notable features are as follows:

* Minimalist shading and canopies,

* Use of open stairways to allow light and breeze,

* Light weight internal walls, easily demountable and provide future retro fit,

* Carport construction that uses simple rigid frames and rafters to reduce the amount of material use,

* Rigid frame handrails with steel expanded mesh and horizontal timber battens allows views, while ensuring privacy,

* Suspended canopies which provide rain protection,

* Galvanised steel weathering strips over windows throw off the rain and allow windows to be open for ventilation in most weather.

The benefits of this kind of ESD detailing are threefold. Firstly the low maintenance, long life approach to the selection of materials provides life cycle benefits. Secondly, there is a craft to the way the materials are built into components and then into sub-assemblies producing an architectural language which is then consistent throughout the units. The repetition and variety of the elements gives a sense of order and tectonic expression to the building further enhancing the feeling of place. There is little evidence of recycled building materials in the assemblies and building by-products selected but the elemental nature of the materials gives opportunity for recycling in the future. There is demonstration of a sensitivity to the eco-efficiency of construction of the building; the materials, components and systems and the units themselves. The buildings take a lifecycle perspective through loose fit long life structures which integrate preventive maintenance strategies to ensure durability. The internal partitions are non-load bearing and demountable which gives future possibilities for change without major structural consequences. The most interesting feature of the buildings is the northern orientated facades. The links between the interior and exterior become blurred, with a large open plan space, connecting living, dining and the deck spaces. The decks are generously designed to make external rooms, which provide a platform for enjoying the external environment. These precious spaces thermal delight within a subtropical climate, where the Queensland lifestyle is not held as myth but is infact legendary.




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