A Lot of Rot

Posted by Allan Vester on May 08, 2018

The issue of leaky buildings is one that just won't go away and an expert report from Jeanette Drysdale on the problem was warmly received. Jeannette, a long serving and very actively involved Rotarian is also highly qualified in the area of timber rot and the regulations and standards associated with the use of timber in construction. 
 
As Jeanette explained it New Zealand was at the centre of a perfect storm. A relaxation of the standards associated with the use of untreated timber in construction, increasingly complicated designs, parapets, enclosed balconies, smaller eaves, increased reliance on paints and sealants, monolithic cladding directly fixed and a raft of new building products, ably supported by architects all combined to lead to what was a disaster. 

With a long background in research into timber rot and a many years as a consultant to the building industry Jeanette has been selected to take a leading role in the committees reviewing two of the standards central to the use of timber; "The chemical preservation or round wood and sawn timber" and "Timber and wood based products for use in building."

Jeanette referred to the 4D's as the key to ensuring that timber in a building remains dry:

  • Deflection of water, 

  • Drainage cavity, 

  • Drying, 

  • Durability. 

Given the need for speed in building and the number of less qualified people involved, the risk that one or more of the "d's" will not be properly met means there is an increasing understanding that treatment of timber is required. The two committees will look at what the standards need too be to meet the New Zealand context. Chemical preservation is clearly the leading approach but they will also look at the viability of other treatment methods including heat treatment. 

Clearly the huge costs, both economic and personal, associated with the leaky homes issue has led to a strong commitment to ensure that our regulations and standards prevent any repeat.