Tried and tested

Durability and Desired Service Life
Though BS EN350-2 does not strictly speaking apply to modified timbers such as Accoya, the BRE have made an assessment that the durability class 1 rating achieved by Accoya wood in these trials is equivalent to class 1 of natural timbers and therefore that service life statements attributed in BS 8417 are applicable to Accoya wood.
Under BS 8417, only cladding made from timbers of durability class 1 is suitable for situations where there is a desired service life of 60 years. Note that because of the variability of durability of these timbers, short of being able to confidently specify a minimum density of the timbers it is not possible to be sure that all of the cladding boards will have a service life of 60 years.
Outstanding Stability
Leading Timber research institute, BM TRADA, tested the Accoya wood against other widely used cladding materials by exposing coated boards to a high humidity environment and letting them acclimate:
- Accoya wood outperformed all other timbers
- On the basis of this and other trials TRADA support the use of thinner and wider boards than with other timbers, e.g. T&G 15mm thick and 195mm wide. This increased width specification board shows Accoya woods’s design flexibility and superior performance when compared to western red cedar, larch and pine.
- Larger spans for brise soleil now possible
- Mitre joints now possible
- Dimensional stability also leads to longer life of film-forming coatings


Scion Outdoor Stake Test
Durability testing is run for extended periods , to local standards at locations across the world including New Zealand. Accoya is tested along side CCA H4, Teak and western red cedar at the SCION graveyard test field in Rotorua. Stakes are inspected on 12 month intervals by the SCION staff and scored on a scale from 10 (perfect) to 0 (totally destroyed). At the 10 year point only colour change has been noted for the Accoya wood samples while all other wood types have either onset of decay or significant decay