Quick answer: Lay timber decking boards only after the frame is stable, level and able to drain properly. Plan the full board run before fixing the first board, choose which face will be visible, leave a consistent 5–8mm gap between boards, use suitable exterior decking screws and re-treat freshly cut ends.
Plan the board layout before fixing the first board
Do not build the whole deck and only then work out where the boards will land. Measure the usable deck width, the actual finished board width and the stock lengths you plan to use before fixing anything.
Our treated timber decking boards finish at approximately 120mm wide and are available in 2.4m, 3.0m, 3.6m, 3.9m, 4.2m and 4.8m lengths. Use the Decking Calculator if you want the boards, framing timber and screws worked out together.
Make sure the decking frame can drain and breathe
The visible boards are only as good as the structure underneath them. Use suitable treated framing timber, provide enough support and keep the frame clear of trapped water wherever possible.
Before laying the boards, check the joist layout and support spacing. Our Decking Joist Calculator can help with common domestic layouts.
Choose which face goes up before you start
Do not assume every grooved board must be installed grooves-up. If both faces are properly finished and the board is genuinely reversible, either side may be suitable. If one face is clearly unfinished, use the properly finished face.
For the full explanation, see Which Way Up Should Decking Boards Go?.
Leave a consistent 5–8mm gap between decking boards
The Timber Decking and Cladding Association recommends a 5–8mm gap between adjacent timber deck boards for drainage and normal timber movement.
Keep that spacing consistent across the deck. Horseshoe packers make simple repeatable spacers, and checking the gap along the full board before fully fixing it helps stop the layout drifting. If the boards are extremely wet or noticeably uneven across the pack, let them settle and dry more evenly before installation.
See What Gap Between Decking Boards? for the detailed spacing guide.
Fix the boards with suitable exterior decking screws
Use exterior-grade decking screws that are suitable for pressure-treated timber. Work methodically along each board, keep checking that the board stays straight and avoid letting small alignment errors build up across several rows.
For current fixings, shop our decking screws.
Re-treat cut ends and keep the finished deck draining
Freshly cut treated timber should be re-treated where possible with a suitable end-grain preservative. Once the deck is finished, keep the board gaps clear so rainwater can drain and air can move around the timber.
Ready to lay the boards?
Shop treated timber decking boards, or use the Decking Calculator to build the main materials list for your deck.
