Managing timber’s moisture content in the supply chain, construction and in service

<p>This is the final summary report for the National Institute for Forest Products Innovation’s (NIPFI) project: NT045 / NIF109 Managing timber’s moisture content (MC) in the supply chain, construction and in service. This project’s objective was to generate informed industry guidance on best practice for the economic and effective MC control of timber and wood products in the Australian timber supply chain. It aimed to identify regular problems and key influencing factors; build an initial knowledge base of equilibrium moisture content (EMC) conditions and timber’s MC performance in the timber supply chain; and generate a refined suite of industry best practice guidance. Timber and wood products in service contain water. The amount of water contained in wood at a particular time is known as its MC. Wood is hygroscopic and timber’s MC will vary with its surrounding conditions. Once seasoned in production, timber and wood products lose or gain moisture to be in equilibrium with the surrounding atmosphere. As their MC changes, their dimensions’ change. Managing timber’s MC is a critical part of its production, use in design and construction, and management in buildings in service. As wood is a hygroscopic material, it’s MC variation and consequent movement are vital considerations in the design of timber-rich objects and the behaviour of timber-rich components in construction. While changes in dimension may be small in any one board or sheet, the cumulative effect can be critical to product performance in an application and to customer confidence.  A broad understanding of MC changes outside of the immediate production environment is relatively limited. An improved understanding of the EMC and ventilation rates of the environments in which timber and wood products are transported, stored, installed or serve can enable companies to take effective preventative action when the risk of damage or loss is high. Industry guidance and practice based on this knowledge can lead to improved storage practices for timber and wood products throughout the supply chain, help maintain sawn-timber and wood products in a condition that satisfies the project requirements, reduces avoidable loss of material or value and ultimately increases customer confidence in product reliability. </p>