Sustainable building and construction
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The building and construction stage covers demolition and site preparation through to construction and internal fitout (plumbing, wiring, cladding, cabinetry and joinery). This stage is when hands-on involvement, either by the architect/designer or yourself is essential.
Below is some information on construction systems and building materials, and useful tips on selecting and working with builders and contractors.
Construction systems
(These tips come from the 'Your Home' Technical Manual.)
‘Construction system' is the term used to describe the combination of materials used to build the main structure of a house, i.e., the walls, roof and floor. Selecting the right construction system for your site and climate is a primary determinant in gaining the thermal comfort, passive heating and cooling and other benefits you desire.
Eco-homes feature a careful combination of the right heavyweight and lightweight construction system combinations to suit the site, its constraints and opportunities.
Heavyweight construction consists of materials such as steel, concrete, brick, stone, tiles, rammed earth, and mud brick. Heavyweight construction generally:
- has higher embodied energy and environmental impact,
- provides great thermal mass capacity (provided it is combined with the right passive design elements and insulation),
- requires greater site disturbance and deeper footings, and
- provides significantly greater longevity than most lightweight construction methods.
Lightweight construction tends to consist of light but strong structural framing materials, such as lightweight steel and timber, which support lightweight, non-structural materials such as steel sheets, plywood or fibre cement. Lightweight construction generally:
- has lower embodied energy and environmental impact,
- is more responsive to external temperature changes,
- usually requires more heating and cooling, and
- are typically more able to be reused and/or recycled at the end of their usefulness in the project.
Construction systems for a more sustainable home
A combination of heavyweight floors and lightweight walls works well for level sites in most climates. Combining floor materials, such as uncovered concrete slabs (not insulated with carpet), exposed to northern sunlight in winter (and shaded in summer) with well-insulated lightweight walls is a very efficient way of creating warmer winters and cooler summers.
A combination of lightweight floors and heavyweight walls works well for sloping sites or to reduce site impact. A lightweight, insulated floor (concrete- or steel-supported suspended timber, insulated beneath and well-clad above) can be combined with footings and heavyweight walls (externally-insulated) to provide thermal mass for effective passive design.
Water has twice the volumetric heat capacity of concrete without as much embodied energy. Consider the use of a combination of lightweight walls and floors exposed to northern sunlight (and shaded in summer) with stored water as the subfloor. This gives the same effect as heavyweight floors without as much embodied energy.
For more information on suitable wall, floor and roof construction systems, visit the Your Home website.