Building an Arch

An arch is a great means of linking two separate spaces, creating a doorway between one garden ‘room’ and another, or showcasing plants like climbers.

1. Lay two of the posts and one of the 50 mm crossbeams on the ground in an upside down ‘U’ shape and measure and mark where you need to drill through them to bolt the crossbeam to the posts. Drill and bolt them together.

2. Screw a temporary 20 mm crossbeam onto the posts. Apart from keeping the posts the right distance apart, the temporary beams will help when moving the finished arch into place.

3. Stack the bracing planks together and mark and drill 5 mm holes through both ends of all of them in one go.

4. Measure and mark on the posts and 50 mm crossbeam where to place the braces (three need to go on the crossbeam and one each ±800 mm from the bottom of the posts). Drill holes into the posts and crossbeam and screw one end of the braces onto them.

5. Follow the same procedure with the remaining posts and crossbeams, ending by screwing the opposite ends of the braces into them. You now have your arch.

6. Drill holes at 200 mm intervals up the posts in order to weave wire to support climbing plants. Use an eye-bolt and turnbuckle to tension the wire.

7. Treat the arch feet with a waterproofing product to prevent rotting and extend the arch’s lifespan. Your arch is now ready to go into the ground.

8. Mark and measure where you want to place it and dig 400 mm deep holes for its feet.

9. Mix one part cement with four parts river sand and enough water for a porridge-like consistency. Fill the holes two-thirds of the way up with the mixture. Push the feet of your arch into the cement, checking with a spirit level that the crossbeams are horizontal. Leave overnight to dry, then back-fill. Remove the temporary crossbeams.

10. Prime the wooden parts of the arch with universal undercoat or wood primer, leave to dry, then paint with two coats of exterior, high-exposure paint in the colour of your choice.