Exploring Sustainable Design

By Graham Hepburn

75 per cent of the existing wall framing and subfloor was retained in keeping with the principle of re-using.

As the owner of a family construction business, Andrew Pepper has become keen on exploring sustainable design and materials.

He sees those principles becoming more important with new builds and renovations so when it came to a major overhaul of his family home he put his money where his mouth is.

With the help of architectural designer Tony Biesiek, of Imagine Building Design, what was once a character home has been extended and rebuilt with a Pasifika/Kiwiana theme and with energy-efficiency and sustainability a priority.

Tony says, “The brief for this house was to alter and extend the existing cottage which was a jumble of styles into a modern family home with a Pasifika theme to show their collection of sculptures and artwork from around the Pacific. Good outdoor living and maximising the sea and bush views were top priorities. All with excellent sustainable design focusing on ‘the five Rs’: Reduce, Reuse, Replace, Recycle and Rethink.”

He says some of the home’s form was dictated by height-to-boundary rules and daylight angles as well as the family’s desire to have the living areas upstairs so they could enjoy the views. An upstairs internal covered deck provides privacy and shelter from the prevailing winds. Andrew and his wife Paula say the inspiration for the rebuild came when they were up on the roof, repainting it. The views up there made the thought of adding another floor appealing and the fact that they had to do the painting made Andrew turn his mind to more sustainable, lower maintenance materials.

“We had the house 10 years before we did the major renovation and in that time we had painted it once ourselves and got it painted by someone else and it is a thankless task,” says Andrew. “To me, it just makes sense to reduce living costs and maintenance.”

With that in mind, the home was reclad with a combination of macrocarpa and ribbed Zincalume® and re-roofed with COLORSTEEL® Maxx® corrugate.

In addition, the soffits have been lined with aluminium to further reduce maintenance. The ribbed Zincalume’s strong vertical lines provide a contrast to the horizontal macrocarpa weatherboards and help to define the more ‘modern’ elements of the house as opposed to the traditional look of the gabled roofs.

The tray profile of the Zincalume® was custom-formed for the project with Tony and Andrew working up a profile that was manufactured by Taranaki Steelformers. The ribs are flashed to hide the fixings to achieve a clean, elegant look. Tony says having a local steelformer supply the cladding and roofing was part of the plan to minimise the ‘embodied energy’ of the home – each panel was custom-made for the job locally whereas using an out-of-town supplier would have meant hours of freight.

Using a lightweight metal roof was a no-brainer for Tony.

“I am a huge fan of corrugate,” he says. “I love the softer finish that it gives. To me it is a default product so unless a client feels strongly that they don’t want that look then that is what I give them.”

He says using a lightweight metal roof was also an easier option considering the fact that they were building over the existing structure of the home. The upstairs level is wooden-framed and independent of the ground floor, which sits on wooden piles. Building this way meant the home’s original footprint could be retained and 75 per cent of the existing wall framing and subfloor retained in keeping with the principle of re-using as much of the existing materials as possible.

While Andrew is keen to explore new materials and innovative technology, he says a lot of sustainability principles are grounded in the traditional approaches to building undertaken by his grandfather Len when he began Pepper Construction in 1936. The business, which was later taken over by Andrew’s father and uncle, was heavily involved in building schools and state houses.

Andrew, who recently took over the firm from his father, says in some ways sustainable building is “going back to our roots”.

“Things like passive solar design and passive ventilation are fairly simple principles,” says Andrew. “But these days people are a lot more aware of sustainability so that is why when it came to our house I thought the best way to learn about it is to do it myself.”

It also gave him an appreciation of what clients face when they push the boundaries.

“Being in the trade you are use to working with budgets but when it’s your house you feel the full sting of the cost especially when the budget goes out the window,” says Andrew. “I wanted to incorporate more sustainable measures but cost became an issue; it was a bit of a learning curve.”

However, for their $500,000 budget, Andrew and Paula have achieved a lot. The home has solar hot water heating, photovoltaic solar energy collectors with inverter to the network grid, wetback wood fire, inverter heat pumps, eco and LED lighting, R1.6 under floor, R4.8 ceiling and R2.6 wall insulation, and argon filled thermally broken aluminium framed double glazing. Rainwater is collected for the garden, which also reduces runoff.

Household water consumption is cut by using low flow fittings. The insulation in the home is 100 per cent recyclable polyester.

The flooring is sustainable bamboo. The macrocapra cladding and the eucalypt used in the decking and ceiling sarking are all from sustainable locally milled plantations.

Tony says sourcing timber from local plantations was not only sustainable - as they could choose the right board lengths - but also enjoyable. “I love that part of the process,” he says. “Going out to the mill, picking out the timber and talking to the guy who mills the timber. And you know with a plantation-grown product that when trees get cut down, more get planted.”

With his home completed, Andrew says he is keen to learn more about building sustainably and incorporating principles such as Lifemark, which promotes building homes that will suit occupants for a lifetime, especially as they enter old age.

He has a bit of a headstart with his home, which now has a lift well incorporated into it in case a lift is required later in life.

Imagine Building Design