How to Lay a Deck

The step-by-step guide from Wood Green Timber

Once your subframe is built and solid, it’s time for the best bit — laying the boards. Whether you’re building a raised deck, a garden seating area, or tidying up an awkward corner, this guide will walk you through the process of fixing down your softwood decking boards the right way.

What You’ll Need

From Us:

• Treated softwood decking boards

• Decking screws or fixings

• Joist tape (optional)

• Fascia boards or trims (if needed)

Tools:

• Drill/driver

• Tape measure

• Circular saw or mitre saw

• String line

• Spacers or offcuts for gaps

• Hammer or mallet

Step 1: Acclimatise the Boards

• Leave your decking boards on-site (ideally stacked flat and dry) for 24–48 hours before fixing

• This lets the timber settle to local moisture levels and helps reduce movement later on

Step 2: Plan Your Layout

• Decide which way you want the boards to run

• Most people run them across the joists and in the same direction as the building for visual flow

• Use a string line to keep your first board perfectly straight — this sets the tone for the whole deck

Step 3: Fix the First Board

• Lay your first board flush to the edge and screw it down onto every joist below

• Use decking screws — they won’t rust and they hold tight

• Fix approx. 15–20mm in from each edge, and drive two screws per joist

Step 4: Maintain Consistent Gaps

• Leave a 5–6mm gap between each board for drainage

• Use spacers or offcuts to keep your gap consistent all the way across

• If the weather’s hot and dry, allow a little more gap — boards will swell when wet

Step 5: Work Across the Frame

• Keep your boards tight, straight, and evenly spaced as you go

• Check your lines every few rows using a string line

• Trim the ends once all boards are fixed, or leave them flush as you go if they’re pre-cut to length

Step 6: Add Finishing Touches

• Add fascia boards around the frame for a clean, finished look

• Sand any rough edges or sharp corners

• Optionally apply decking oil or sealer to help preserve the timber and reduce surface wear

A Few Handy Tips

• Always pre-drill near edges if you’re worried about splitting

• Don’t butt boards too tightly — give them room to move

• If you're butting boards end-to-end, make sure each join lands on a joist

• For larger decks, stagger joins for a neater finish

Need Materials?

We stock the full decking package:

• Treated softwood decking boards in a range of lengths

• Decking screws and clips

• Joists, posts, and framing timber

• Fascia trims, weed membrane, postmix and more

If you’re not sure what you need, bring your measurements and we’ll help you work it out.

Pop into Wood Green or Potters Bar, or call the team — we’ll get you sorted.