Poster puts leaks in place

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Poster puts leaks in place

27.07.2002

By ANDREW LAXON

Simple building and design improvements can save your new home from leaks

and rot, says the Building Research Association.

Experts believe thousands of homes built in the past decade have leak and

rot problems, with one in 10 new homes potentially at risk and a national

repair bill that could easily top $1 billion.

In April, an independent inquiry for the Building Industry Authority urged

immediate action to solve the problem, which it blamed on technical issues

and shoddy building practices.

Now the association, which advises the building industry, has produced a

poster for builders, councils and homeowners which shows 10 areas of risk

and how to reduce them.

It says leaks are most likely to happen in houses on elevated or exposed

sites with strong winds.

Multi-storey buildings with complex designs are susceptible, especially if

they do not have eaves to deflect rain from walls.

Other potential design problems are parapets and balconies, which can allow

water to slip through gaps.

Most problems occur with one-piece outside walls (referred to as

" face-sealed cladding systems " in the poster) such as fibre cement, stucco

or polystyrene, if they do not have gaps between the timber framing to allow

water to drain away.

The association advises homeowners and builders to use H3 treated timber -

which protects against " moderate decay " and is the standard already required

for decks - in all high-risk areas to stop rot spreading if leaks do occur.

The authority, which oversees the Building Code, also plans tougher

temporary regulations requiring H3 timber to be used on exterior wall frames

and wall frame bottom plates unless builders can come up with an equally

waterproof alternative.

Many of the association suggestions involve using metal or plastic flashings

instead of sealants to waterproof joins between materials - a point stressed

as crucial in the independent report to the authority.

Association weathertightness manager , who also chairs the

industry's steering group on the issue, said most homeowners would be

familiar with metal or plastic head flashings at the top of aluminium

windows.

Other examples were roof flashings around chimneys and sill flashings under

windows or on balconies.

He said homeowners and builders often filled these gaps with sealants

because it was cheaper and looked better than a strip of metal or plastic.

But although some sealants were good quality, they had to be applied very

carefully to avoid leaks.

* For a copy of the poster ring the Building Research Association on 0900

59090. Information is also available on the website Weathertight or in Build

magazine.