Double-brick houses are typically built with double brick walls, timber windows and timber framed floors on stumps. Double-brick walls are constructed of two skins of brickwork with an air gap in between. Brick has thermal mass properties, meaning that it takes heat from the sun and releases it slowly into your home overnight.
This slow release of heat can be great for comfort even during summer, as the house warms up during the day and cools off at night. During extended hot spells, however, the heat can build up in the walls and release into the home for days afterwards, resulting in an uncomfortable internal temperature.
Double-brick homes have a lot of character, but they also have lots of gaps where air can escape, such as decorative vents. It is important, therefore, to consider draught proofing when renovating your double brick home.
Assumed improvements to existing double-brick style home with 138.5m2 floor area in Melbourne climate zone, 'always home' usage profile, Lee, T., Wu, C., Guthrie, K. and Dewsbury, M., 2014
Best practice draught proofing, either do-it-yourself or done professionally, is the most cost effective option for double-brick homes. Aim to seal up air vents in walls and fireplaces in particular.
Although most double-brick homes have some form of ceiling insulation, renovating to best practice standard (R value 5) should be a priority.
Timber floors are fashionable but can be a source of air leakage during winter. Consider floor insulation if you have underfloor access, or carpets and rugs over original timber floors.