Timber Coatings
Before laying decking the top surface and ends of joists and all sides and ends of decking boards should be treated with water repellent preservative or oil based primer – as detailed in Figure 3. An alternative for joists, is to flash the top surface. For further information on applied finishes contact proprietary manufacturers or for general information refer to the Hardwoods & Cypress Technical Specifier's Guide (referenced at the end of the document).

Deck maintenance is required to prevent leaf litter and other debris from affecting long term durability. To improve service life, use widely gapped boards (10mm gaps) and kerbs spaced well above deck level. This lets the debris pass through – often under wind assistance. Another problem can be brown staining from hardwood leachate. This can be minimised by sealing the timber or providing protection to relevant structures. Another approach is to use cleaning agents to manage the problem. In all cases severity of the problem reduces over time.
 

Figure 3: Pre-deck laying treatment of timber