Timber which is preserved or treated is classified for different uses. Use Class 3 & 4 (UC3/4) are  both for exterior use with 4 being the best treatment option available. From mid 2023 as standard practice we only use UC4 on our sub-frame timber installs.

All cut ends are also re-treated before installation to maintain 100% treatment coverage. 

The final part of the DEX service is a layer of decking tape. The tape we use creates a waterproof barrier on the top surface of the timber sub-frame, this reduces water ingress and further increases the life expectance of the structure.