How to build a garden bench

Video by Wickes. This guide draws on "How to build a garden bench and table with Wickes" from the official Wickes UK channel. It covers the full build from frame to finished seat in clear steps, with good detail on the fixing sequence — particularly useful for anyone tackling this for the first time and wanting to get the angles right before cutting.

1. Choose the right timber

For outdoor use in the UK, you need either pressure-treated softwood, hardwood such as iroko or oak, or a naturally durable species like western red cedar. Treated softwood is the most affordable and widely available from builders’ merchants and DIY stores.

For a standard two-seater bench, you will typically want 75×75mm posts for the legs, 75×38mm for the rails, and 75×25mm or 100×25mm boards for the seat. Pick through the pile at the merchant and avoid anything with large knots near the ends or obvious warp.

2. Cut the legs and seat rails to length

A standard garden bench seat sits at around 450mm from the ground. The legs need to be slightly longer to allow for the rail joints. Cut all four legs to the same length using a mitre saw or a circular saw with a fence — matching lengths are the difference between a bench that sits level and one that rocks.

Cut the front and back seat rails to the overall bench width, and the side rails to the depth. Typical dimensions are 1.5 metres wide and 450mm deep, but adjust to suit your space and the number of seats you want.

3. Build the two end frames

Assemble each end frame flat on the ground. Position two legs with a side rail between them at the top, and an optional lower rail for bracing. Pre-drill all holes before driving screws — this prevents the timber splitting near the ends, which is one of the most common mistakes with outdoor furniture builds.

Use 100mm exterior-grade screws and apply a waterproof construction adhesive to the joints for extra strength. Check each frame is square by measuring the diagonals — both should be equal. Clamp if you have the clamps; let it set for an hour before joining the frames together.

4. Join the two frames with the long rails

Stand both end frames upright and connect them with the front and back seat rails. Again, pre-drill, glue, and screw. This is where an extra pair of hands is genuinely useful — holding two frames upright while you drive screws is awkward on your own. That said, wedging the frames against a wall works fine.

Check the whole structure for square before the glue goes off. A diagonal measurement across the top opening will tell you immediately if the frame is racking.

5. Fit the seat boards

Lay the seat boards across the top rails with an even gap between each — a 6mm spacer cut from scrap timber keeps the gaps consistent. Leave an overhang of around 20–25mm at the front and sides for a finished look.

Pre-drill and countersink each fixing point before driving screws. Two screws per board end, per rail. Countersinking lets the screw head sit flush or just below the surface so there are no sharp edges and the treatment can penetrate cleanly.

6. Sand and apply a wood treatment

Run a belt sander or an orbital sander over the whole bench, working through 80 and then 120 grit. Pay attention to any sharp edges and arrises — round them slightly so the timber feels comfortable to sit on and grips treatment better.

Apply an exterior wood oil or preservative treatment following the tin instructions. Two coats is usually recommended for new timber. Allow each coat to soak in fully before applying the next. Re-treat annually for a bench that stays looking good and resists rot for years.

When to call a handyman

Call Richard if you want a bench built from hardwood to a bespoke size, if it needs to be fixed to a wall or deck, or if the project involves a matching table and you would rather not spend the whole weekend cutting and measuring.