By Jo Bailey
Weathertightness of structures has been a hot topic in New Zealand since the leaky building crisis became public in 2002.
New Zealand Institute of Building Surveyors (NZIBS) executive member Nick Gaites says it is impossible to tell the exact numbers of homes affected.
However, the weathertightness expert says after years immersed in the problem, he believes well over 90 percent of building stock with direct fix monolithic (plaster) claddings built in New Zealand between 1991 and 2005 are potentially problematic, particularly two storey ‘Mediterranean’ style homes with no eaves.
“I’ve had lots of people tell me they have a plaster house, but it’s not a leaky building. Unfortunately, it probably is. There is a misconception that in order to be a leaky building it must have water dripping through the ceiling and mould growing inside. This is absolutely not the case because it is the condition of the structural elements that are hidden behind the walls and not visible from the outside that tell the true story.”
Nick says even small amount amounts of water trapped between the wall cladding and the outside of the timber frame will have an impact over the long term.
“Behind the wall things can be slowly rotting away without any internal signs. This is partly the reason why so many houses remain unfixed as people genuinely don’t believe they have a leaky home.”
In his day-to-day job as a director of Reveal Building Consultants, Nick has seen some sorry sights when wall cavities are opened up in these homes.
“There have been instances where wall framing is completely black, composted, decayed and full of ants, worms and centipedes. Yet from the outside the house looked fine.”
Nick says the problems often aren’t revealed until renovations or extensions are being carried out.
“We know of instances where the issues aren’t apparent until a project is well underway. The builder may have foundation and framing works completed for an extension, then breaks into the existing building to connect the extension, to find it has been leaking. Work has to stop in order to remediate the damaged framing, which requires changes to the scope of works, new design details and a building consent amendment.”
This is problematic for both the homeowner, in terms of time and cost delays, and the builder, who may have to find other work or lay people off when the project is put on hold.
Nick says homeowners and builders about to start any building project on a plaster-clad home built between 1991 and 2005 should seek independent, impartial advice from a Registered Building Surveyor before work begins.
“An independent survey and due diligence carried out up front by a building surveyor in consultation with the homeowner can result in big savings in the time and cost of a job. A Registered Building Surveyor can also provide a peer review of the design of the new addition to ensure the proposed work is weathertight and durable and that the project runs smoothly.”
Nick says the experience of NZIBS Registered Building Surveyors when it comes to weathertightness is what sets them apart.
“It was NZIBS that first lifted the lid on the leaky building crisis and in the years since, our Registered Building Surveyor members have gained significant experience and expertise in dealing with these problems. We understand in detail how buildings perform with regard weathertightness and how to fix them.”
Nick says there have been “too many instances” where building inspectors from other organisations without this knowledge base and training to fall back on get it wrong.
“This doesn’t help anybody.”
He says the rigorous process, including intensive training that building surveyors must undertake to become registered with NZIBS, is a key point of difference.
“I believe the NZIBS training is unsurpassed for quality, detail and technical content, and that we are the best trained body of surveyors in the country.”
In addition to a high level of forensic diagnostic investigation and reporting, Registered Building Surveyors also provide weathertightness remedial design and peer review, and appear as expert witnesses for plaintiffs and defendants.
Nick says the leaky home syndrome is still a “massive problem” with the end of the leaky home repair fund bad news for New Zealand housing stock.
“Only a fraction of the potentially affected houses have been fixed. The demise of the financial assistance package means many won’t be, which further degrades the existing housing stock. This leaves a lot of homeowners, and future owners of these buildings out in the cold.”
He says any homeowner intending to repair their leaky home should seek the advice of a Registered Building Surveyor.
“The cost of fixing a leaky building is very high and you only want to do it once. Seeking professional advice is key to getting it right first time.”