Study of mass transfer and hygroscopic properties of Australian mass-timber panels and species in hot and humid conditions- moisture sorption and desorption

ABSTRACT

Wood is a commonly used building material with numerous advantages over other construction products. However, in engineered wood products such as cross-laminated-timber and laminated veneer lumber moisture absorption can lead to decay, swelling, deformation, and glue line failures, diminishing their properties. Understanding moisture intrusion processes in these materials can aid manufacturers, engineers, and architects in developing effective moisture management strategies during and after construction. The porosity of CLT 3P sections was 56.5%, higher than CLT 2P sections at 36.8%. True density varied among species, with radiata pine, southern pine, and shining gum measuring 1358, 1411, and 1031 kg/m³, respectively. True density values for CLT 3P, CLT 2P, and LVL were 1202, 837, and 1406 kg/m³, respectively. The species and sample type significantly influenced porosity and density values, crucial for future moisture modelling and predicting moisture gain/loss during wetting and drying processes. Moisture sorption and desorption properties were examined for Australian timber species, CLT, and LVL at different temperatures. LVL samples exhibited higher moisture content and dimensional changes, possibly due to improved moisture transfer facilitated by lathe checks. CLT samples demonstrated greater anisotropic behaviours than those of LVL samples. The product type and sample type had significant effects on equilibrium moisture content values.

KEYWORDS:

• Sorption isotherm
• mass timber panel
• cross laminated timber
• laminated veneer lumber
• solid boards
• timber species

Acknowledgements

The author acknowledges the National Centre for Timber Durability and Design Life for its funding support. The author would also like to acknowledge the technical support provided by the Forest Product Innovations team at the Queensland Department of Agriculture and Fisheries Salisbury research facility.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported as part of the project titled “Investigating the effects of moisture ingress on the performance and service life of mass timber panels in Australian climates” funded by the National Centre for Timber Durability and Design through Forest and Wood Products Australia.