Category Archives: Earthquake

Sobering tales about repairs

If you have niggling doubts about the standard of your EQC inspection, don’t ignore them.

That’s the advice from a bunch of building professionals I recently interviewed for Progressive Building magazine, a trade publication which commissioned me to write an article about the repair process after it became aware of mounting criticism from builders, architects and engineers.ProgressiveBuilding

Their concern is that major damage is being missed in homes given quick “rake, stop and paint” makeovers which will deteriorate down the track, eventually landing us with a quake-induced version of the leaky homes saga.

Take the home owner told his big tilt slab house needed only a cosmetic fix taking six weeks. Fortunately he listened to a builder mate and had an architect take laser levels which revealed parts of the house had dropped 60 mm. The barely perceptible line in the lounge floor – which the EQC inspector dismissed as “carpet bunching” – was where the slab had split and after spending $7000 on further investigations initiated by the owner, insurers accepted the house was a write off.

Of particular concern are large multi-level hill homes.  Sometimes the damage is not obvious and is only visible after removing sections of gib board. EQC says owners must pay if removal of gib does not reveal any damage – but for my money, sacrificing a sheet or two of gib is a worthwhile investment if it provides peace of mind.

One of the architects I spoke to recommends that owners of architecturally designed homes ensure that inspectors scoping their properties are supplied with the original drawings so they are aware of joins between major structural elements.

Many Christchurch homes had slabs poured onto “tailings,” larger rounded river stones which tended to settle in the shakes, opening up voids which make floors sound hollow or “drummy.” BRANZ has decreed that tailings can no longer be used for this purpose, but exactly how this problem can be fixed in affected houses remains to be seen. The injection of expanding resin is one possibility.

Home owners are also advised to request documentation of any repairs so when they come to sell the house, they can provide potential purchasers with proof of the remedial work. Although the council would like unconsented repair work entered on its property files, this is not compulsory, so future home buyers need to be savvy about asking for information before signing any purchase agreements.

Take the case of repairs involving asbestos, which is found in a whole range of building materials, particularly stippled ceilings. Removing asbestos-containing ceilings is a messy and expensive business because of the need to prevent the rest of the house and furnishings being contaminated with asbestos fibres (long associated with a form of cancer).

One option is to install a false ceiling over the damaged asbestos. Again it is not compulsory to notify the council that asbestos is present in a home, but if you don’t put this information on the property file, that potentially puts future owners at risk. What say a keen DIY-er or a tradesman drills through the false ceiling to install new down lights and ends up being showered with asbestos? Would you want that on your conscience…I’m darn sure I wouldn’t!

Sumner Rocks – Our boulder problem

The Sumner Rocks T-shirts, bumper stickers and street party were great morale boosters, but behind the fun slogan lies the cold reality that the boulder problem is a big one.

Liquefaction has hogged the headlines, but the threats posed by unstable cliffs and rocks on the Port Hills will be tricky and potentially very costly to fix.

That was brought home to me during research for a North & South story (in the latest issue of the magazine) when I spent a morning with a geotech crew working on a hillside above the Summit Road. The previous day we’d had a 3.8 quake which had shaken loose large boulders that previously seemed quite stable and it was an eye-opener watching the crew using air bags, crow bars, explosives and a fair bit of physical grunt to shift unstable rocks.

The Christchurch City council has promised to have answers by the end of June for more than 500 red stickered property owners whose homes are in boulder fall zones or on dodgy cliff tops, but chances are it will be some time before proposed rock protection measures materialise.

Last year local geotechs visited the Swiss Alps to view rock protection methods, including sophisticated steel mesh fences with braking systems. A quote to build one of these fences in Morgan’s Valley was about $1.9 million; however, given its potential to protect some very expensive homes, it could be a worthwhile investment.

Money, of course, will be a huge issue. If homes have to be abandoned, who is going to compensate owners for dwellings which often have little or no damage? The council official I interviewed argued that homes deemed uninhabitable because of rock fall or cliff collapse should be offered the same deal as red zoned homes affected by liquefaction, but that’s a policy decision for the government.

And what about the insurance companies? Christchurch lawyer Dr Duncan Webb believes that where broadly worded insurance policies refer to “physical damage or loss,” there is a strong case for insurers to pay out on undamaged but uninhabitable homes.

He says this scenario is almost identical to a case where undamaged mining equipment was trapped behind a 100 metre rock fall when a mine collapsed. So if a large teetering rock threatens your home, the fact that the rock has not yet gone through the middle of your house makes no difference to the fact that it cannot be occupied, therefore insurers should pay.

Whatever the outcome we have to face the fact that, even if the ground stops shaking, rocks will continue to fall, as they have done for years. In the eighties a large chunk of the rock face below (now closed) Edwin Mouldey Track fell without warning in the middle of the night. Pre-quakes, boulders (including some very large ones) regularly fell on to properties in Heberden and Wakefield Avenues, especially after heavy rain. Unfortunately the quakes have loosened things up and if we get a wet winter there is the very real possibility of further rock falls. Hooray for shipping containers – they may be ugly, but at least they work!