Building within a budget

February 2013

"Bad news! Since the last issue of Green Ideas we have discovered our house design is unaffordable. We are gutted! Justin, Kate (the architects), Helen and I worked really hard to come up with an interesting yet modest design, and one that sought to save costs and help the planet by using lots of recycled goods.

In the last issue I wrote about what the Christchurch earthquakes have taught us about ‘listening to the land’. Our house build has also benefited in a very practical way through us sourcing many recycled goods from quake-damaged homes. But now we are hitting the challenging part of building in post-earthquake Christchurch.

We tendered the project out to three builders. The first contractor – recommended to us by our architect for their eco credentials – was $170,000 over our budget. The second contractor, a local firm (we liked the idea of supporting local businesses and the smaller carbon footprint as they don’t have to drive as far to get to our land), was a little more competitive, but still $100,000 over our budget. Digging further we found that some subcontractors are charging extremely high rates due to the current demand on their services; the third contractor didn’t even bother to put in a quote (this happens, we’re told). We eventually replaced him with a small building firm that our neighbour recommended.

Where to cut?

We start trying to cut costs and decide to take out all the concrete blockwork in the house design (some perimeter wall foundations) and replace it with wooden-braced foundations and retaining walls. This produces a significant saving. We also decide to do all interior and exterior painting ourselves – another big saving.

Then we opt to cut the decking down by 80 per cent and make it radiata instead of macrocarpa (both are sustainably harvested, but radiata is more unstable and needs the usual chemical treatments). We get rid of some (sob!) lovely wooden shelves we were having built-in to the northern interior wall of the house.

We’re getting much closer, yet we’re still over budget!

We sit down again to look at where we can save costs. Is there anywhere else we could make a saving without compromising on the basic feel and idea – a warm, spacious cottage ‘sitting lightly on the land’?

We turn our knives to the bigger ticket items:

• Sewage and water system. Perhaps we should give away the idea of harvesting our own rainwater which, however wise and economical in the long-term, involves some start-up costs. Perhaps we should give up our idea of treating our sewage onsite – this is a costly system, but paying to connect to council mains may be just as costly where we live. 
• Cladding. Perhaps we should investigate cheaper forms of cladding than macrocarpa board and batten (even though this is a durable, local, sustainably-harvested product).
• Interior ceiling profiles. We have some lovely sloping, raised pitch ceilings. If we opted for flat ceilings this would be a little cheaper.

We decide that to change our sewage and water system would be very unwise. It might give us some short term savings, but long-term it may cost us a lot more and we really don’t want to miss this opportunity to make our house more sustainable in how it uses basic resources. (We’ve already put off solar panels for another day, i.e. when we win Lotto and can really fling the green magic wand around). As for the ceiling profiles, Helen is determined to preserve these and I offer feeble resistance. We decide they are really important to the aesthetic feel of the house and will only let them go if there’s no other option. So it’s the cladding.

We spend a fortnight (feels like years) exploring cheaper cladding options:

• Radiata board and batten. Comes from sustainably harvested and managed forests, cheaper than macrocarpa, but less durable, is a treated timber and needs more painting long term.
• Plywood. Probably the cheapest timber cladding option, comes from sustainably harvested and managed forests, can look quite thin and industrial, can feel quite unnaturally rough and processed, can use quite a lot of glues in production, can weather quickly.

We hum and ha and remain unconvinced on both.

Finally, our architect breaks the deadlock: What about keeping macrocarpa board and batten on the large gabled walls of the cottage, and using another material on the other walls, a cladding material that looks great when paired with natural timber, suits the New Zealand countryside, is competitively priced, performs extremely well in earthquake conditions, is extremely durable and requires very little maintenance? And the material is?

Two more clues:

1. This cladding is a standard choice for new and old buildings in Iceland, from cottages and churches to pubs and civic buildings – where its earthquake and fire resistant properties are much prized.
2. This cladding was also locally used in Lyttleton (just 15 minutes around the harbour from us at Governor’s Bay) following the 1870 town fire that destroyed many of the wooden buildings, and performed well throughout the recent earthquakes.

Yes, the answer of course is ‘corrugated iron’, ‘tin’, ‘profiled metal cladding’. Call it what you will, it now clads two-thirds of our cottage-to-be. While not as cheap as we had hoped, it will save us some money now (and more in the long-term), and eke us over the line.

We shake hands with our builders-to-be, the firm our neighbour put us in touch with, and look forward to getting the building under way. Sure, we now have no contingency budget (well, almost none), but at least we’re not over budget (well, not at this point), and we haven’t had to sacrifice the core environmental character that makes this building worthwhile for us."

Handy links

Article on corrugated iron in green buildings
Corrugated iron in New Zealand