How to build a gabion rock retaining wall for your garden

Replace a damaged old garden wall with this rock-steady option!

When it comes to building a retaining wall there are so many styles and materials on offer. From sandstone to brick, you’re spoilt for choice. However not all walls are created equal. Some eventually crack under pressure, leaving an ugly sight. 

The solution? Replace the old wall with this reliable, easy-to-build gabion look-alike. It’s made from painted timber sleepers, with pebbles tightly packed behind a mesh screen.

Gather your supplies

  • 150 x 75 x 2400mm H4 treated-pine sleepers (7)
  • 1800 x 1200mm handy panels of 75 x 50 x 4mm wire mesh (2)
  • Nepean river pebbles
  • Exterior paint (we used Dulux Weathershield Low Sheen in Black)
  • 100mm bugle head batten screws
  • 2mm galvanised U-nails
  • Selection of plants (we used Syzygium ‘Select form’, Lomandra ‘Tropic Belle’, Pennisetum ‘Moulin Rouge’ and agave)

You’ll also need

Hammer; bolster; spade; shovel; crowbar (optional); mattock (optional); stringline; pegs; set-out paint; spirit level; quick-set concrete; post-hole digger; garden mix; mulch; geotextile filter fabric roll; angle grinder; sledgehammer; circular saw; cordless drill


1. Before you start, check with your local council for building regulations.

2. These instructions are for a 6m-long sloping wall with tallest bay measuring 475 x 1200mm. Adjust material dimensions and quantities to suit your needs.

Here’s how…

Step 1

Break up sections of old wall with spade, crowbar or mattock. If section being removed is connected to an adjacent wall, use hammer and bolster to cut off. Remove footing and clean out rubble and major plant roots, if any. Excavate soil approximately 300mm behind existing wall, to lower ground level.

Step 2

Widen excavated trench to allow for double thickness of sleeper, plus room for stones behind wall (at least 1m in total).

Step 3

Hammer in pegs at ends so stringline will extend at least 1m beyond wall on each side. Run stringline between pegs to mark back of vertical posts. Adjust height to desired level of wall.

Step 4

Paint sleepers in 2 coats of exterior paint. Allow to dry between coats. Use set-out paint to mark 1200mm intervals along side of trench. Using post-hole digger, dig a 400mm-deep hole at each marked interval, roughly 150 x 200mm in size.

Step 5

Use circular saw to cut six 800mm posts from 2 sleepers. Position in holes and secure with concrete, checking they are plumb with 400mm above ground.

Step 6

Once concrete is set, cut posts to correct height for a level wall (here, 75mm below stringline).

Step 7

Measure distance from midpoint of 1 post to midpoint of next (here, 1200mm). Use angle grinder to cut mesh to size, matching difference in post heights. Fix to back of posts with U-nails.

Step 8

Cut 1 sleeper in half. Put 2.5 sleepers, on their narrow edge, in front of posts at ground level. Screw to posts.

Step 9

Screw remaining 2.5 sleepers along top of posts as capping. Keep flush with post fronts and set half piece at opposite end to half piece at ground level. Secure wire mesh to underside of capping with U-nails.

Step 10

Remove turf from along top length of wall and lay down geotextile fabric.

Step 11

Fill wall with pebbles, in stages, packing tightly and pulling geotextile fabric taut before backfilling with soil. Plant up area with selection of plants and mulch.

Final look!

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