The existing construction is plastered concrete blockwork walls on a concrete slab with a suspended concrete mid-floor (including mid-level concrete terraces), aluminium single-glazed window joinery and a membrane roof. Being on an exposed, west facing site the house over heated in the summer and was too cold and draughty in the winter. The renovation will be within the existing building footprint.

The building envelope was upgraded with an external insulated plaster system on blockwork, a warm membrane roof and high performance Passive House certified timber-aluminium joinery with high performance double-glazed low-E low G-value (high shading coefficient) glass. High performance double glazed joinery was chosen with an interior insulating timber frame and an aluminium exterior face for weather protection and to reduce maintenance.

The double glazed joinery, wall, roof, and floor components have a high level of airtightness.

The Blower Door Test measured airtightness of 1.0 air change per hour, which meets the EnerPHit requirements.  Conventional building code house is approx. 5.0 air change per hour.

Ventilation is controlled through the use of a mechanical heat recovery ventilation system. This will ensure excellent indoor air quality and control the internal temperature, humidity and comfort level of the occupants.

Particular attention was paid to remedying or reducing the effect of the thermal bridges in the existing structure including concrete terraces over internal habitable spaces, the concrete floor slab and cantilevered steel and timber roof structure. A thermal bridge is like a heat super highway that creates an easy path for energy to escape from the warm interior to colder exterior.