Disputed timber resisted rot in tough test, claims expert

A controversial new wood product failed to decay much when exposed to the harshest testing conditions for 185 weeks, says an industry expert.

Terry Smith, technical sales manager from Osmose NZ, which manufactures the timber preservative marketed as TimberSaver, said latest test results showed the strength of the wood.

TimberSaver is used to treat T1.2 wood, but doubts about the new product arose this week when National MP Nick Smith warned of a second wave of rotting homes, after the leaky homes scandal.

His warning was backed by scientist Robin Wakeling, who said the surface spray did not penetrate wood as well as traditional soaking and was liable to wash off if the timber became wet.

In response, Building Issues Minister Chris Carter asked the Department of Building and Housing to investigate and prepare a report, due soon.

Terry Smith's defence of TimberSaver was yesterday backed up by Jeanette Drysdale, an executive council member of the International Research Group on Wood Protection and the independent expert who reviewed test data on the new product.

She has called for an end to hysteria over the use of TimberSaver.

Terry Smith said T1.2 timber was subjected to the worst possible conditions for 185 weeks yet it performed almost exactly the same as boron-treated timber, proving its strong resistance to rot.

The test results were released last month by Forest Research in Rotorua, he said.

Several types of timber were exposed to the most threatening conditions of moisture and heat.

Untreated timber rotted within 104 weeks, but TimberSaver wood retained a soundness rating of 9.5 out of 10 after 185 weeks.

"This proves that suspicions about this timber are completely ill-founded," Mr Smith said.

Jeanette Drysdale called for calm over the issue.

"I am very concerned by the recent hysteria that has arisen regarding the acceptability of the TimberSaver product due to ill-informed comment," she said.

"Independent experts at Forest Research tested the product and after reviewing their test reports, supporting documentation supplied by Osmose NZ and data available on boron-treated timber from previous research, I am confident that this framing product will perform extremely well."

Dr Wakeling said yesterday that he knew of the tests but still put little stock by them.

The tests were just a research tool and not extensive enough to enable the new product to be introduced.