The complex challenges of hillside renovations

What started as a small-scale renovation, updating the front door and entry, turned into a whole of house renovation and 100 square metre extension to an existing 269 square metre hillside home.

Building new on a steep hill site would present plenty of challenges. These were amplified for a renovation of an existing house spread over five levels, on a site with restricted access (a long, shared driveway requiring careful scheduling of sub-contractors and site visitors), poor ground conditions (that necessitated temporary support structures to enable the build) and foundations that were also retaining walls and therefore required waterproofing.

Richard Fantham of Radius Building says a primary concern was identifying the potential issues far enough in advance to enable solutions to be found to avoid additional cost and expenses.

“This renovation project took more thought than any other job”, says Richard. “The complexity of renovating the existing house and successfully connecting it to the 100 square metre extension challenged us to identify all the problems before we started demolition and reconstruction.”

Part of the complexity is created by not knowing what lies beneath the walls, ceilings and foundations of older houses built to different building codes. The existing building may no longer be compliant and that means materials may need to be replaced or modified to bring it up to code. Sometimes the only way to find out what needs to be remedied is to rip off the cladding and take a look. The complexity of this renovation is best illustrated with the many intricate joins between levels (floors, ceilings and rooflines) and rooms (walls, doors and windows).

“This renovation required a thorough understanding of the fundamentals of building science in order to create unprecedented building compliant solutions”, says Richard Fantham. “There were at least 50 details in the house that weren’t illustrated in any building code or guides. We had to draw on all our experience, particularly our knowledge of weathertightness products and options, to ensure we could deliver a compliant completed renovation.”

An added complication was that the renovation grew as it progressed. The owners decided to fully renovate the entire house part way through the project and add in extra features such as an inbuilt stereo system, later in the project than would normally be sequenced.

None of these complexities prevented Radius Building from successfully completing the renovation and transformation of a 1980s house into a modern spacious home. The extension over the green roof of the garage has created a large, light-filled kitchen/dining area with large sliders opening to an exterior deck over the balance of the green roof. The open-plan living space has two large sliders opening onto a generous tiled outdoor patio with glass balustrading and tiled stairs leading up to the higher levels and down to the driveway.

The newly built areas of the house are connected to the existing wing with a double-height atrium. While some of the existing brick cladding has been retained, the Oregon weatherboards have been updated with Cedar, and plaster over Hebel block has replaced the plastered polystyrene.

“The owners loved the location and views”, says Richard. “Now they’ve got a home that’s equal to the location without having to move. Renovation can be a viable option for houses with good bones. You just need to talk to your builder about what’s feasible so any issues can be identified in advance and solutions found before they cause extra costs and expenses.”