There’s beauty to creating a wall from a pile of stones and knowing, if done right, it will stand the test of time. Building dry-stone walls is an ancient practice, providing a practical solution to making terraces and raised garden beds or shoring up slopes. The natural finish of the stones visually complements most landscapes.
Stone wall construction is like fitting together a giant, three-dimensional jigsaw. The pieces are very heavy, so take your time and look after your back.
A good-looking, stable wall depends on stone selection. Choose square, chunky stones as these jigsaw together better than round or oval shapes. The best walls have minimal gaps. Use different sized stones for different parts of the wall (see Diagram 1, below). You can buy them at landscape supply centres.
Select base stones about 300-350mm long, wall stones about 250-300mm long, capstones or headstones about 200mm long.
Buying stone is straightforward. It is often stacked on pallets and sold by the square metre. Larger feature rock pieces can be bought individually. Check your local listings for landscape supply centres.
Establish the line of the wall with pegs and stringline, then cut back the slope. At the base, dig a 200mm deep, 600mm wide trench. Separately pile topsoil and subsoil nearby to make it easier to backfill later. Fill the trench with a 100mm bed of 20mm aggregate. TIP: The line of a straight wall can be set with pegs and a stringline.
Lay large base stones along the outer edge of the trench. Now is the time to roll in any rocks that are going to be too big to lift up onto the upper courses. TIP: Separate stone into size groups for faster selection.
Tuck geotextile landscape fabric in behind the first course, fold it over the rocks, shovel in backfill and tamp soil by pounding with a post or plate compactor. Repeat this entire process after each course. TIP: If the site is wet, lay a length of agricultural pipe behind the base stone so that any water will be diverted to an exit point.
Lay the fabric back against the slope and set the wall stone courses. Each course should be wider than the previous one. Three courses are shown here. TIP: It’s best to complete an entire course before moving on to the next (see Diagram 2).
Drive chinking stones or wedge stones into the face of the wall to fill any gaps or secure loose rocks. When doing this, wear safety glasses to protect eyes from flying shards of stone. TIP: For a more balanced effect, use small pieces or wedges to fill holes.
Lay capstones, checking with a level as you go. Capstones should bring the wall to a height that is roughly level with the embankment. Mortar small capstones in place for permanency. Tuck the fabric in behind the capstones, backfill and add topsoil. TIP: Lay the capstones to a stringline to ensure they’re level.