Borer and leaks plague 60 per cent of inspected Wellington homes

Last updated 18:40 23/04/2017

An investigation of Wellington's housing stock has found earthquake concerns in 60 per cent of 100 inspected homes.

Wellington City Council chief resilience officer Mike Mendonca says council still needs to investigate further before the extent of housing stock vulnerability is known.
Council building intelligence manager Derek Baxter said psychological research showed being displaced from your home was more psychologically damaging than being displaced from your workplace.
Brian Clifford owns four pest eradication services around Wellington and has been tackling borer infestations for 27 years.

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Sixty per cent of inspected Wellington homes have earthquake or weather resilience issues, according to an inquiry into the capital's housing stock.

Inspections were carried out on 100 city homes over two years, and results were concerning enough to prompt Wellington City Council to line up 500 more homes for inspection before the end of the year.

Council chief resilience officer Mike Mendonca said borer infestations, poor weather proofing and insecure foundations were the main issues.

"All of those things worry us, from a weather and earthquake perspective. We are really keen to encourage home owners to have a look at this stuff," he said.

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Half of the inspected homes had some degree of borer infestation, Mendonca said, with many having major infestations. 

"If you have that in your framing, obviously your house won't be as strong."

Mendonca said non-weathertight homes had been an issue for decades in New Zealand, and all efforts to address the issue to-date had received poor uptake.

"Homes that aren't weather-tight aren't resilient. If a non-weathertight home is tested in a decent earthquake, there's a greater chance of that home failing."

The full extent of the problem was not yet known, Mendonca said.

The resilience team was compiling information from the Earthquake Commission (EQC), Massey University and research institute Branz, and planned to present more information to councillors before the annual plan process in June.

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Mendonca said one of the biggest obstacles to creating resilient homes was that owners didn't want to know about their property's risks.

"If you think about it from a homeowner's perspective, if you're trying to sell, you're probably better off not knowing," he said.

"We tend to be consumed with the look and feel of our home rather than its foundations."

Council building intelligence manager Derek Baxter said research showed being displaced from your home was more psychologically damaging than being displaced from your place of work.

Council figures estimate between 5000 and 7000 residents were displaced from their workplaces after the Kaikoura Earthquake, but most were able to continue working from home.

"We're not being totally altruistic here, we want people to feel safe in their homes, but we also need to keep our economy ticking over," Mendonca said.

The Business and Economic Research Limited (BERL) had done high-level analysis of the cost of residential home failure in a quake, and found for every $1 spent in preparation, $4 was saved in a big quake scenario.

"It's pretty compelling that investing in our homes pays off in an earthquake, what that doesn't cover off is the public policy question of who pays," Mendonca said.

Brian Clifford, who owns four pest eradication services around Wellington, said it was not uncommon to find homes with heavy infestations, particularly in roof trusses and below floor level.

"I found two last week, one was in Berhampore that was very badly damaged, and one was in Karori," said Clifford, who has been in the industry 27 years.

Homes that were often in shadow or in damper areas were more likely to be infested.

Clifford said homes built between 1939 and 1953 were more at-risk, but anything before 1962 was vulnerable.

Treating the underfloor and ceiling areas of a home usually cost around $900, Clifford said.


  • Make sure your house is fixed to its piles - this means checking floor joists are nailed to foundations.
  • Check the condition of your roof - older heavy-weight tiles may have moved after recent earthquakes, so it is worth checking for wear, and dislodged tiles which may have created leaks. Tin roofs should be checked to make sure fixing nails are still in good condition.
  • Get under your house - this is often where you discover borer, and dampness is a sign of poor drainage or weather proofing.
  • Borer leave small pinprick holes in wood. Homes can be fumigated to combat borer, but it is often more effective to use wood treatment directly applied to timbers.
  •  Check the land on your section - if you are on a hill, check for cracks in the ground. If you have a retaining wall or a terraced garden, check it hasn't moved, it is adequately sunk into the ground, and it has drainage pipes built into it.
  • Look out for stains on wallpaper, leaks around windows and doors, and damp areas.
  • Make sure your hot water cylinder and heat pump is secured, as well as any large items like bookcases, televisions, or large hanging mirrors.
  • Have old brick chimneys checked to make sure they are secure.
  • Check added underfloor storage areas or sheds - any damp or alterations to piling from DIY alterations are a risk.

- Stuff


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