An estimated three-quarters of the capital's homeowners may have to find thousands of dollars each to make their homes more earthquake-proof if a new Wellington City Council proposal goes ahead.

The plan would require a Government law change so the council could target dodgy foundations, shonky chimneys and poorly supported roof tiles that could cause injury or death in a quake.

Related story: Ernesto cafe to close for earthquake-strengthening

A law change would have implications not just for Wellington homeowners but for those everywhere in New Zealand.

The council has no legal powers now to enforce earthquake-strengthening measures over single-family homes.

The proposal is in a scoping paper to decide the parameters of a review into the council's policy for earthquake-prone buildings, called for after the devastating February quake in Christchurch.

The current council policy objective is for occupiers of commercial buildings to be able to get out safely during a moderate earthquake. There is an option for the council to continue down this path, but council officers are recommending a much wider review to include residential homes.

A 2008 report co-authored by Victoria University senior lecturer Geoff Thomas highlights a major problem with the safety of homes should the "big one" strike.

The report said about three-quarters of Wellington homes had problems with their foundations, which would cost more than $290million to fix.

However, doing so would limit damage from a significant quake to about $1.8 billion – $2b less than if the strengthening work were not done, the report said.

The council built-environment portfolio leader, Iona Pannett, said a big quake in Wellington would have a significant impact on homes, just as it had in Christchurch.

"The risks of hill slips, chimneys and foundations are the big issues ... but we aren't going to be rushing on to people's properties saying they have to strengthen their foundations.

"We are taking a calm and considered approach to look at it."

The council is bound by the Building Act 2004, which has a focus to protect lives by preventing buildings from falling down in a disaster. Ms Pannett said that focus was too narrow and the act needed to include standards that also protected buildings.

More than 30,000 Christchurch houses were believed to have suffered chimney damage in the September quake. Thousands more were damaged in the February quake. The average cost of removing a chimney was about $400, Shane Kerslake of Christchurch firm Rentabloke Property Services said.

Some homeowners would struggle to pay for the strengthening of their foundations and the council has made it clear that it also does not have the funds.

It might ask the Government for funding or to be a partner in a loan scheme if the Government included family homes in its earthquake policy.

The scoping paper also suggests the Government change tax law to make the cost of strengthening a deductible expense.

The revised earthquake-prone-building policy is not expected to be endorsed until mid-2013.

The royal commission of inquiry into the Christchurch earthquakes and a part-completed Building and Housing Department report would frame any council decisions, Ms Pannett said.

Commission of inquiry executive director Justine Gilliland said it was focusing on Christchurch's CBD, but would make recommendations about building types and materials, including unreinforced masonry, for other other cities.

QUAKE POLICY

Safety in and from commercial buildings during moderate and major earthquakes

Safety in and from private dwellings Preservation of heritage buildings

Maintaining and enhancing economic and community vitality

Maintaining and enhancing character and streetscape values

Minimising economic disruption from a major quake

Ensuring building failures do not impede emergency response following a major quake

Rules shake-up needed?

Building Act 2004 dictates that old buildings be strengthened to 33.3 per cent of the strength of a new building But buildings between 33.3 and 67 per cent are still at risk of major failure in a moderate quake

Some buildings may require treatment beyond 100 per cent of the code to protect them in a major quake Building owners can choose not to restrengthen and to "demolish the building by neglect"

Even strengthened buildings may be at risk from surrounding buildings that are unstrengthened. Source: WCC scoping paper

- © Fairfax NZ News

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