How to build a garden wall

Key points before you start

  • Get professional advice if you are in any doubt, particularly with walls over 1.5m high and complex or stress carrying structures.
  • Plan the wall and draw a design; this helps with calculating quantities and makes building quicker.
  • Get the right tools; spade, concrete mixer, trowel, spirit level, club hammer, 60-120mm bolster chisel, stringline and pointing tool.

A firm foundation is essential

  • Walls need a concrete foundation three times wider than the thickness of the wall. Its depth should be at least 100mm with the base 300mm below ground level.
  • For walls over 1m high the foundation base depth should be one third of the height of the wall above ground.


  • Single skin walls 100mm thick should not be higher than 1m and need 215mm square piers every 2m.
  • Walls over one metre high should be double skin construction, with the two skins tied together and should have support pillars at least every 3m.
  • All walls need provision for expansion and contraction about every 6m.
  • Protect the top of the wall with copings and pier caps or suitably sized paving slabs.

Bricklaying, Mortar & Joints

  • Use normal bricklaying techniques including damp proof courses where appropriate.
  • Mortar should be 1 part masonry cement to 4 parts soft bricklayers sand.
  • Mix bricks/blocks from different packs to ensure a blend of shades. If using just one pack, select from the top down.
  • With raised planters and retaining walls, leave some vertical joints un-mortared for drainage.
  • Raised pools require a waterproof liner and a design that will support the weight of water.
To Top