Sustainable design comes in many forms. Maintaining an existing building is one very good form of sustainable design. It becomes even more pertinent when the existing building is a late 1800’s heritage workers cottage located in Fremantle. Although in this instance the building was heritage listed and our clients were compelled to maintain the existing cottage, we should always try and maintain existing buildings where possible.
The existing limestone structure was an unrecognizable mess when our clients discovered it. The gorgeous limestone walls were covered over by 1 inch of plaster and tack on additions were everywhere. Our clients did an amazing job of stripping it back and bringing the building back to its former glory.
Our extension design consisted of a ground floor open plan kitchen, dining and living area with 3 bedrooms and 2 bathrooms to the first floor. Except for the concreted ground slab, the entire structure is constructed from renewable timbers. Even the window frames are timber. By using all timber, which is a great insulator, heat transfer in and out of the building is minimized. The entire addition is a box, which also provides minimal external surface area further reducing heat ingress or egress.
There is one downside of utilizing an all timber structure for the construction of a home in Perth or south of Perth. Lack of thermal mass will mean passively heating the home will be a little more difficult than say in a reverse brick veneer type construction. The concrete slab does provide a reasonable amount of thermal mass and it was enough to get this home past the NCC (National Construction Code, previously the Building Code of Australia or BCA) rating system. Had the home been larger it may have been more difficult. As with all Ecohabit homes, the building was designed with the occupants in mind and their lifestyle so the rating system really isn’t as important. What is important is the occupants stay comfortable without requiring much energy input, which they do.
As the site is very compact and the outdoor areas quite minimal it was very important that when the living areas opened up they connect directly with those small external spaces. This was achieved with the use of bifold doors and windows, however heat loading from these small areas needed to be considered. Concrete breeze blocks were used, laid on their side and filled with soil.