guide to the specification, installation and use of preservative treated ...

Page | 8
GUIDE TO THE SPECIFICATION, INSTALLATION
AND USE OF PRESERVATIVE TREATED
ENGINEERED WOOD PRODUCTS
failure. The performance of EWPs can be dramatically affected by exposure to various hazards in a
“normal” building environment. In particular, exposure to insects and/or fungi can result in significant
loss of section and therefore strength. Prolonged exposure of EWPs to weather and moisture can
result in significant degrade of product over the medium to long term.
Buildings properly specified, designed, constructed and maintained using EWPs can be expected to
provide excellent performance over the life of the structure. This document is intended to provide
designers, builders and other users of EWPs with simple and appropriate guidelines to help achieve
the goal of structural performance.
Product selection
Treated Glulam
pedestrian
bridge, Ås,
Norway
(Courtesy Timber
Queensland)
Correct design and specification of treated EWPs involves a number of steps as outlined in Figure 1.
Each of the stated steps are presented in some detail to provide guidance to designers. Critical to the
design process is the need to consider
durability. This will require consideration of
both the product durability and the
environment in which it will be exposed during
its service life.
Decorative H3 treated plywood cladding
(Courtesy CHH WoodProducts Australia)
Australia has a performance-based building
regulation framework as set down in the
Building Code of Australia (BCA). At this time
the durability performance requirements are
not directly specified, but are implicit.
Durability is a key consideration for
construction materials in any modern building
project. According to the Australian Building
Codes Board, in their guideline document
Durability in Buildings,
“Durability means the capability of a building or
its parts to perform a function over a specified
period of time.”