Lifestyle: What we need now is watertight thinking

A flashing detail on a new window in our renovated home. Photo/Supplied

Hindsight, as we all know, is 20/20, and the leaky homes crisis in New Zealand lends itself easily to such clear retrospective viewing.

According to Wikipedia, "The repairs and replacement cost that could have been avoided were estimated in 2009 to be approximately $11.3 billion."

From an eco-thrifty perspective, this is infuriating because it represents such a waste of money and resources, mostly attributable to bad design and "changed building controls from a prescriptive system to a more self-regulated regime".

We all know what happened when world governments allowed banks to regulate themselves over the last several decades: they crashed the global economy. But instead of reining in banks, the United States and Europe have allowed them to get bigger and to reward their executives with ever larger bonuses.

Thankfully, the New Zealand Government did not respond to leaky homes in the same way. Some say the NZ Building Code is now among the toughest in the world, and building inspectors are known to be thorough in their attention to detail.

I have praised the building code on a number of occasions as quintessentially sustainable. After all, a sustainable home is one that won't rot, won't fall down in an earthquake and has a level of energy-efficiency.

Architects and builders have known for hundreds of years the importance of shedding water away from wooden structures, and it's not just about roofs. "Flashing" is the term for sealing up all the bits around doors and windows as well as unusual junctures in complex roofs or around chimneys, flues and relief valves. Attention to detail is vital because any seam in the building envelope is a possible entryway for water.

Good, thorough flashing costs time and money, but pays for itself in "cost avoidance" in the future ($11.3 billion and counting). It is almost always cheaper to do something properly the first time instead of cleaning up the mess and making repairs later on. Water damage is expensive.

To draw a parallel from housing to our greater community, the stopbanks (aka levees) along the Whanganui River act as flashing for our city. They are designed to transfer floodwaters safely out to sea. Recently, Whanganui District Council reinforced the 50-year stopbanks along Anzac Parade while Horizons engineers have reported that because of climate change, a 50-year flood is now a 25-year flood, a 100-year flood is a 50-year flood, a 200-year flood is now a 100-year flood.

I'm sorry if this is all starting to sound like "The artist formerly known as Prince" talk, but it appears that we've entered a new normal that includes more frequent and severe droughts and floods as well as persistently high fuel costs to deal with the responses to both.

That would appear to require different ways of thinking from what local government has given us in the past. In other words, we may need new thinking to address the new normal.

A prudent observer might say time is of the essence. With a halving of flood intervals, it appears the clock is now ticking twice as fast.

Nelson Lebo consults schools, businesses, homeowners and larger property owners on all aspects of sustainability and eco-design. theecoschool@gmail.com

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