Timber treatment survey results
The Department is reviewing whether treated framing meets the needs and expectations of the building and construction sector.
In February 2008, we asked people working in the industry to comment on:
- timber identification and quality assurance
- choices for treated framing
- handling LOSP-treated timber
- boron treatments
- the weather exposure of treated framing.
The survey indicates there are clear industry preferences in critical areas of timber treatment, and confirms our own assessments that improvements are needed in the supply and use of treated framing timber. We are planning a review of NZS 3602 Timber and Wood Based Products for Use in Buildings. In the shorter term we are also commissioning a testing programme on the performance of H3.1 boron-treated framing. Also, ERMA and the Department of Labour are helping the Timber Preservation Council review their LOSP health and safety information sheets and the treatment industry's Best Practice Guide for flash-off. ERMA and the Department of Labour are also working with industry to reduce and eliminate the active preservative Tri-n-butyltin in LOSP treatments.
The full survey report is available for download from our website, www.dbh.govt.nz/technical-reports
The report explores the responses to all 14 questions, together with the many associated comments people made.
The graphs opposite summarise a selection of the survey questions.
Note: all graphs may not total 100% as some respondents indicated that some questions were not applicable to their work.
Question 1. What best describes your involvement in the construction industry?
Question 2. Are the differences between H1.1, H1.2, H3.1 and H3.2 clear to you?
Question 3. Do you require more or less choice in timber treatments for framing
Question 4. How do you know that the LOSP treatment has flashed off to a safe level?
Question 6. If a boron-based treatment was available for the H3.1 treatment class for timber framing, would you use it?
Question 8. Should there be maximum recommended exposure periods for timber framing left open to the weather during off-site fabrication, delivery and the construction period?
Question 9. How practical is it to require builders to use site-applied treatments to cut or notched timber framing on the job?