The Big Cottage with a Small Footprint

The Christchurch earthquake saw a shift to lightweight roof designs. “The earthquakes changed our choices as we’d never do a heavy roof now.” Bob explains of his decision-making process, “A light roof was always going to be the way to go, in terms of earthquakes, mass is your enemy.”. The interlocking design of Gerard’s roof tile creates a strong single structural unit intrinsically safer and sturdier than loose concrete tiles of the past.  The benefit of going with a steel tile roof is the reduction in building materials required to support the roof “If you’ve got a heavy roof, you’re inherently going to have to have a heavier wall structure and bracing to support the roof.” Bob says.

The overall roof design is a key element in ensuring energy efficiency and liveability in the home.  The design of the Big Cottage utilises a clever roofing feature to minimise overheating in the warmer months. An engawa, a roofed verandah-like structure that wraps around the building was designed, leaning on Japanese architectural practises.  “The engawa really is fundamental.  It’s crucial in preventing overheating.”  Bob explains “It’s actually quite easy to do a warm home, but it’s more difficult to make it so that it’s not going to be too hot in summer, and the engawa is essential in preventing that overheating by blocking the midsummer midday sun on the north side, and allowing enough sun to come in during the winter when the sun is at a lower angle.”  Nestled into the engawa roof is a large skylight, positioned to allow light into the kitchen and dining area where more natural light is needed, further reducing the power demand on the home.

Additional features are peppered throughout this project such as rainwater harvesting off the roof.  From a Superhome perspective, this is a must-have. “It’s so easy to do and doesn’t cost a lot, so you might as well make use of the water.” Bob says of rainwater harvesting “We’re using it as irrigation for the garden as a minimum. Then the next step is to plumb it in to flush the toilets because in the average home half the water is flushed down the toilet.” Gerard’s steel tiles are an ideal fit for this feature, as both smooth and textured finishes are safe for rainwater harvesting.  Additionally, all Superhomes are outfitted with solar panels to ensure energy is being captured and utilised within the home. Gerard has an innovative bracketing system which allows solar panels to be mounted with brackets hooked under roofing panels to eliminate the need for roof penetrations which may cause degradation of the roof over time.

The project now stands completed with Vickie and John enjoying their new home. And showing their passion in furthering the education around sustainability and a better way of building, they’ve since had the annual Superhome Tour feature their home as a stop – the same tour they took before building the Big Cottage. Bob reflects on the project “It was a privilege to work on it and work with John and Vickie. They loved their house and at the end of the day that’s the ultimate reward for us.”.

Photography by Lightforge Photography.