Common design in Perth, Western Australia would see your average house constructed from double clay brick with standard glass in aluminium windows. The reason for this would be cost and common acceptable practice, be it right or wrong.
If cost wasn’t an issue the sustainable design alternative for the area would be reverse brick veneer with low-emissive (low-e) glass in plastic coated (on the outside) timber window frames. Double-glazed windows are not necessary in Perth because we don’t experience extreme cold temperatures.
Reverse veneer is a realistic and sustainable building design in Perth. This allows for an excellent outdoor layer of thermal insulation around the house while providing a high thermal mass on the inside to keep in heat stored in the internal brickwork and concrete, allowing it to be released slowly – unlike a wall with no mass such as a timber framed wall, which changes temperature quicker. To stop heat loss around the edges of the concrete slab, the face of the slab should be lined.
Normal window systems can easily be protected from the sun and weather by using oversized eaves, awnings and patios on the west and east sides. Eaves on the north side will shade the windows in summer while still allowing the winter sun to penetrate the inside of the house. The use of tinting on the hotter west and east sides would help to stop heat transfer into rooms in summer. Well lapped heavy drapes in winter should be used to stop heat escaping through the glass from the inside in winter. Plastic clad timber framed windows have the best insulation factors and would be the best product to use, though are very uncommon in Perth. Once again heavy curtains impervious to air flow will assist in stopping the transfer of heat through an inferior frame. Prevention of heat gain through better shading is an alternative to the cure of expensive frames.
Insulation batts would be used on the ceiling with sarking over the rafters which will stop the transfer of heat through the roof cladding into the roof space. The ceiling batts, mass brick walls and concrete floor create a stable environment within the house that is not susceptible to large temperature changes and maintains heat retention in winter.
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Due to constantly evolving legislation the information provided within this blog may no longer be valid. The advice given on this site is general in nature and does not take into account your specific circumstances. Please email one of our building surveyors to check what is right for you.