Timbersaver Proven Effective As Other Treatments
12 July 2005
Timbersaver Proven As Effective As Other Wood Preservation Treatments
Consumers and homeowners can be confident that TimberSaver treated wood is a durable and proven solution for house framing, according to the product’s manufacturer, Osmose NZ.
Osmose NZ’s Technical Sales Manager, Terry Smith, said the surface-applied boron treatment has fully complied with the requirements of the Department of Building and Housing.
“TimberSaver has been part of trials alongside H1.2 products which show TimberSaver is just as effective, and in some cases more effective, than the H1.2 treated timber.
“We strongly refute claims made in the media that wood treated with our product is not durable. We are extremely concerned that New Zealand homeowners and the building industry are being unduly panicked by the release of incorrect and inflammatory information,” he said.
Wood treated with TimberSaver has been independently tested under severe wet and warm conditions for more than three and a half years at Forest Research (now Scion) in Rotorua. These tests prove that the decay resistance of TimberSaver treated wood compares favourably with wood treated to an H3.1 standard, and exceeds some H1.2 treatments.
Additional trials that exposed TimberSaver treated wall frames to rainfall for three and six months show that the surface-applied preservative in TimberSaver is no more prone to wash off than other standards-approved H1.2 boron-based treatments.
“As an international leader in the wood preservation industry, it is extremely concerning to us that prior to recent media reports regarding TimberSaver, Osmose NZ was not approached by the parties criticising the product to provide any product information or test results which prove the effectiveness of TimberSaver,” he said.
Five CODEMARK product accreditations have been issued to date for the product by the Department of Building and Housing, acknowledging that TimberSaver treated framing meets all requirements for durability under the New Zealand Building Code, and may be used as an Alternative Solution to H1.2 treated framing. This is also supported by a third party peer reviewed independent appraisal report.
Smith said Osmose NZ will work closely with the Department of Building and Housing over the coming days.
Background on Osmose
A private-owned corporation headquartered in the United States, Osmose has been a producer of timber preservatives since 1934 and is now the world's leading manufacturer and supplier of timber preservatives, with operations in over 30 countries.
11 July 2005
Background On Timbersaver
Treatment of radiata pine house framing with boron has been widespread in New Zealand since 1958. Virtually all framing, up until the early 90’s, has been treated with boron. The use of boron as a wood preservative fell away in the early 90’s as the use of untreated framing was introduced.
Recent changes to building standards have seen the return to a requirement for a significant amount of decay resistant framing for houses. The use of boron has been growing steadily over the last two years. Boron is now approved in NZS3640:2003 for H1.1 and H1.2 situations, both of which are situations in which the wood is in normally dry conditions.
The intention of H1.2 treatments is to prevent rapid decay occurring should the framing become wet due to water leaks during the life of the building, to allow the homeowner time to restore weathertightness, without having to undertake major structural repairs on decayed framing. Structural wood that is intended to be exposed to continually damp situations during normal service must be treated to H3.2 or higher Hazard Class level.
Osmose New Zealand commenced trials in 2001 with a new version of boron treatment, which is marketed as TimberSaver. TimberSaver differs to conventional boron treatments in that it is applied to and absorbed into the wood surface, forming a reservoir of preservative within the wood. Due to the ready mobility of boron, this material can then be carried further into the wood should it become wet during its service life. A similar product, known in New Zealand as FrameSaver, has been BRANZ appraised as a suitable product for remedial treatment of wood e.g. during repairs to leaky homes. Similar products have been sold around the world for this use for decades.
Wood treated with TimberSaver has been independently tested under severe wet and warm conditions for more than 3 ½ years at Forest Research (now Scion) in Rotorua. The same trials also included the now common LOSP H1.2 and H3.1 treatments, and data from this trial was used to support the approval of these products through New Zealand Standards. The results of these trials show that the decay resistance of TimberSaver treated wood compares favourably with wood treated to an H3.1 standard, and exceeds more common H1.2 treatments. The Appraisal notes that TimberSaver treated wood should be exposed to rain for no more than two months during construction to prevent losses of boron that may compromise future performance. This is clearly communicated down the supply chain to ensure those working with the product are aware of the correct use of this product.
However, additional trials were undertaken to more fully understand the properties of TimberSaver and to determine benefits and limitations. This has included studies to evaluate the rate of leaching (removal) from wood under rain exposure as would occur during construction. The trials exposed wall frames to rainfall for three and six months. These trials have shown that the preservative in TimberSaver is no more leach-prone than other conventional, standards-approved H1.2 boron-based treatments.
On the basis of these trials and other scientific data, a third-party product Appraisal was written by an independent wood preservation expert, Mrs Jeanette Drysdale, which supported the use of TimberSaver treated framing as an Alternative Solution to H1.2 treated wood. Mrs Drysdale has had a lifelong career in mycology and wood preservation, and is a member of the NEW ZEALAND Standards Committee for NEW ZEALANDS3640, and also a member of the International Research Group on Wood Preservation.
The information package was then reviewed in-depth by experts at the Building Industry Authority (now Department of Building and Housing), as well as two overseas wood preservation experts, all of who endorsed the performance claims made for TimberSaver in the Appraisal.
Five CODEMARK product accreditations have been issued for the product to date by the Department of Building and Housing, acknowledging that TimberSaver treated framing meets all requirements for durability under the New Zealand Building Code, and may be used as an Alternative Solution to H1.2 treated framing.
Copies of the Appraisal have been widely distributed through Building Certifiers and Territorial Authorities, and via the supply chain from manufacturer to retailer and end-user. TimberSaver treated wood is required to be visibly different and readily identified so that it is not easily confused with other treated or untreated wood. For this reason it is coloured bright orange, and bears the words “TIMBERSAVER BORON” as a face brand every 1500mm down the length of the wood.
TimberSaver treated wood has been in commercial production at three sites in New Zealand since April 2004. Application methods are covered by a comprehensive quality assurance system which is third party audited.
TimberSaver treated wood is offered as an Alternative Solution to H1.2 treated wood. Performance testing has been conducted by scientists at Forest Research using methods specifically designed to simulate the worst conditions in New Zealand’s leaky homes. Its uses and installation are covered by a comprehensive and peer-reviewed Product Appraisal, and it has been Certified to meet the requirements of the New Zealand Building Code for durability by the Department of Building and Housing. Consumers and homeowners can be confident that TimberSaver treated wood is a durable and proven solution for house framing.