Quest for weathertight houses blamed for leaky homes crisis

By ANNE GIBSON

Overrestrictive building rules are partly to blame for rotting homes, say construction industry executives.

Lockwood Homes executive chairman Joe La Grouw and Construction Industry Council chief John Pfahlert said yesterday that the Building Code needed overhauling.

The push to create energy-efficient homes had resulted in houses so tightly insulated and without any air flowing through their cavities that they were prone to retaining moisture and eventually rotting, they said.

"The quest for a completely weather-tight house ... is an unrealistic and damaging requirement of the Building Code, which only adds to the problems caused by the use of monolithic claddings and plastic gunk in Mediterranean-style homes," La Grouw of Rotorua said yesterday.

"The Building Code needs to be realistic and practical about what is and is not achievable with modern materials in building site conditions, not a theoretical construct which only applies in the testing labs," La Grouw said.

He also recommended an overhaul of company law to stop developers and building companies avoiding liability.

His comments were backed up by Pfahlert of the council in Wellington, whose formation was announced last week.

He said the council would today issue more details of measures planned to stop the rot.

The council is a new group of various industry authorities representing builders, architects, engineers, the Building Industry Association and other professional and trade bodies.

Pfahlert, who is also head of the Contractors Federation, said the Building Code was overprescriptive and this was one area his council wanted overhauled.

"Older homes tended to have a degree of air circulation around windows and doors, which was quite healthy," Pfahlert said.

"Now we have to install special devices to create adequate air ventilation."

Mr La Grouw said most houses leaked to some extent.

"Water comes in through the exterior walls or because moisture cannot escape from inside the house. Water will penetrate the exterior walls of a house, even if it is painted and sealed. That's not a problem if the building system lets the water get out, but it becomes a major issue if it is sealed into insulation within the walls - the insulation just gets sodden and rots the untreated timber in the framing.

"Water can get into a building through the smallest crack or pin hole in an exterior wall, despite the use of modern coatings or plastic sealants. Inside a house, the fact that people breathe means moisture is generated which has to go somewhere. Seal that moisture in and your home will soon smell damp. That's why so many people need humidifiers in their homes these days, when no one needed them in the past.

"The trick is to recognise realities and design a system which uses the flow characteristics of water to help that water get out on its own," La Grouw said.

Lockwood Homes would continue to build houses using treated timber and creating pressure equalisation joints and draining cavities, which channel water out of the building if it gets in, he said.

La Grouw was sceptical about the Government's proposals for a new rotting homes mediation service, predicting that developers and builders would avoid liability by refusing to join mediation.

"Try to get any of them into a mandatory mediation scheme and see how many turn up for the first meeting," he said.

Many builders were changing the structure of their companies to avoid liability, "using $200 shelf companies", he said.

His criticism was backed up by Subcontractors Federation chief Peter Degerholm, who said yesterday that he was concerned about the responsibility of developers and builders in the rotting homes crisis.

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Further reading
Feature: Leaky buildings

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