Specification and use of wood-based panels in exterior and high humidity situations

Specification and use of wood-based panels in exterior and high humidity situations

Date Published

17 August 2022

Document Type





Certain types of wood-based panels can be used in demanding exterior situations. However, they must be correctly specified, detailed, installed and maintained, in order to provide the desired performance and service life.

Exterior use covers a wide range of situations. They may be fully exposed to wetting by salt or fresh water or be more protected with a risk of occasional wetting, such as soffits under porches or lorry decks.

This Wood Information Sheet details the considerations which must be made when specifying wood-based panels for exterior use, in particular whether a preservative treatment or protective measure is required to extend service life.

Key Information

Appropiate specification is the main consideration when using wood-based panels in high humidity and exterior situations.

There is a range of risk factors for wood-based panels associated with high humidity and exterior applications that are not present for applications in dry conditions.

Plywood is the panel product most likely to be specified for exterior use, but its specification must consider the bond quality, the biological durability of the veneer species and the need for any additional preservative treatment or coatings.

Case studies

The new visitor and education centre at Brockholes Wetland and Woodland Nature Reserve near Preston is set on a floating ‘island’ on a lake. The design, by Adam Khan Architects, won an RIBA competition and was inspired by the now-destroyed magical landscape of the Marsh Arabs in Southern Iraq, recorded by the anthropologist Wilfred Thesiger in the 1950s

Dominating the Bradford skyline is a group of magnificent Grade II* listed Victorian buildings, Lister Mills, with massive stone walls and an iconic 250 foot high chimney, inspired by St Mark’s Campanile in Venice.