Landscape and Urban Design Issue 45 2020 | Page 50

DECKING NEW HIGHER SPECIFICATION FOR DECK SUBSTRUCTURES The specification requirements for pressure treated softwood deck substructures are set to change in BS8417, the British Standard for wood preservation, when it is next revised with leading trade bodies incorporating the changes now. This means that all softwood beams, joists, wall plates, blocking and bracing will have to be pressure treated to the same level as posts that are in permanent contact with the ground, a category referred to as Use Class 4. This brings the UK into line with standards in Sweden, Finland, France and north America where the whole deck substructure system (posts, beams and joists) is recognised as safety critical. TDCA members are working to adopt this change in policy in readiness for the publication of the revised BS8417, probably in 2021. Leading the way, Use Class 4 joists are already available from TCDA members Hoppings Softwoods, Silva Timber and Champion Timber. The question is how many decking installers will pick up on this new requirement and ensure that the work they undertake meets the latest standards? Certainly, TDCA DeckMark accredited installers whose work is inspected to ensure compliance, will be fully conversant. To find a DeckMark accredited installer or enquire about achieving accreditation, email [email protected] or visit the TDCA website www.tdca.org.uk where you’ll find a UK supplier search facility. 50 www.landud.co.uk Follow us @ludmagazine