Good Practice in Wall Construction

I was thinking about building a garden wall and did some investigations as to a solid construction. Here’s a diagram I put together with some notes on the composition. Note this is a consolidation of my online investigations. Similar construction would be suitable for an extension although that would involve further widening of the footing and blockwork on the inside tide to a concrete slab. I will do another post on foundations for your typical extension.

1. Foundation (Footing)

  • Depth: At least 300–450 mm below ground level (deeper if soil is poor or prone to frost heave).
  • Width: At least twice the wall thickness (e.g. a 215 mm wall should have ~450 mm foundation).
  • Material: Concrete strip foundation (often 1:6 cement:ballast).
  • Purpose: Spreads load, prevents settlement and tipping.

2. Damp Proof Course (DPC)

  • A damp proof membrane or layer of engineering bricks placed 150 mm above ground.
  • Prevents rising damp and frost damage to softer facing bricks.

3. Brickwork / Blockwork

  • Single-skin half brick wall (102.5 mm thick): Weak, suitable only for low decorative walls.
  • One brick thick wall (215 mm): Much stronger, suitable for higher freestanding walls.
  • Bond: Use stretcher bond with piers or English/Flemish bond for strength.
  • Engineering bricks recommended at base courses.

4. Piers (Buttresses / Pillars)

  • Spaced every 2–3 metres along the wall for stability.
  • Width: One brick square (215 × 215 mm) or more.
  • Height: Same as wall, bonded into the brickwork.
  • Purpose: Prevents bowing or collapse in wind loads.

5. Copings / Cappings

  • A solid weathering detail at the top of the wall to shed rainwater.
  • Options: Stone, concrete, or specially shaped coping bricks.
  • Should project at least 45 mm beyond wall face with a drip groove underneath.

6. Drainage and Expansion

  • For long runs, expansion joints may be needed every 6 m (brick) or 12 m (block).
  • Drainage at base (weep holes) if wall retains soil.

And you have probably seen engineering bricks in the sides of buildings before but here’s a useful picture diagram