Currently being used as a weekend home, the owners of this charming rural cottage wanted to renovate and extend so that they could comfortably reside there permanently.
Being in close proximity to the foothills of the Tararua ranges, a key requirement was to make the home warm and comfortable year-round. As well as a high-performance modern extension comprising of a kitchen, dining, and utility space, the rest of the cottage also required increased thermal performance.
To achieve this, an exposed polished concrete slab was specified for the extension. The XPS insulated slab will act as a ‘thermal mass’, storing excess heat from the sun and the interior air, and releasing it once the interior air temperature drops. This passive design feature will help with temperature regulation and heating in an economical and efficient way.
An exposed interior concrete block wall will also act as thermal mass, and benefit the rest of the home. It will surround the fireplace to help store heat generated, then transfer it through to the master bedroom on the other side. The heat transfer through the concrete block wall will also work to heat the south facing master bedroom in winter when the sun hits the concrete block wall on the lounge (north) side.
The building envelope is also crucial to achieving further thermal performance. 140mm and 190mm framing will be used for the external wall framing, along with a rigid air barrier (RAB), and wool insulation in the walls and ceiling. A warm roof system has been designed for the new roof for its high levels of insulation and high-performance qualities (such as shifting the dew point). The new aluminium joinery is thermally broken with Low-E glass.