Which timbers are most suitable for use as external cladding?
There is a wide range of softwoods and hardwoods that can be used for external cladding. The issues to consider are the natural durability of the timber, its moisture movement, hardness, brittleness, environmental credentials, and availability and cost may also be expected to be important considerations Timbers that are commonly used include:
European redwood (Pinus sylvestris) European whitewood (Picea abies) with suitable preservative treatment. European larch (Larix decidua) can be used untreated (providing sapwood is excluded), as can Douglas fir (Pseudotsuga menziesii) if imported from North America (homegrown Douglas fir requires treatment). One of the most popular softwoods is Western red cedar (Thuja plicata), a naturally durable timber that can be left untreated, although sapwood still needs to be excluded.
Suitable hardwoods include European oak (Quercus spp) and sweet chestnut (Castanea sativa) as well as a wide range of FSC-certified tropical hardwoods, including Angelim, Cumaru, Louro, Itauba, Jatoba, Kauri, Massaranduba, Purpleheart and Tatajuba. These hardwoods are all classified as durable or very durable and can therefore be used without additional preservative treatment, providing sapwood is excluded.
A number of ‘modified' timbers are also suitable for cladding use, including heat treated and acetylated softwoods.
For more detailed information about timber cladding, take a look at our book External Timber Cladding, a comprehensive guide to the design and specification of timber cladding.
We also provides a range of services for building designers and product manufacturers to assist with timber cladding queries, as well as training and cpd.
