Garden and boundary walls: foundations, height and piers
Part of our brick walls guides
A garden wall looks like the simplest brickwork there is, which is why so many of them lean. Free-standing walls are exposed on both faces and have no roof holding them down, so foundation, thickness and piers all have to be right.
Foundations
A free-standing wall needs a concrete strip foundation sized for its height and the ground it sits on, taken below the level affected by seasonal movement and well clear of tree roots where possible. Clay soils shrink and swell more than most, which is why a shallow foundation that survived one summer can crack after a dry one.
Thickness, piers and height
A half-brick wall is only suitable at low heights. Above that it needs piers at regular centres, or a full one-brick thickness, or both. Piers should be bonded into the wall rather than tacked on, and the spacing set out before the first course so the panels between them come out in whole bricks.
Under permitted development in England, walls next to a highway used by vehicles are generally limited to one metre, and elsewhere to two metres; conservation areas and listed buildings differ. Confirm with your council.
Details that keep it standing
The details at the top and bottom decide how long the wall lasts.
- A damp proof course near the base to stop ground moisture rising into the brickwork
- A coping or capping that overhangs both faces and throws water clear
- Movement joints on longer runs so thermal movement does not crack the wall
- Weep holes and drainage where the wall retains any ground
- Mortar weaker than the brick, so the joint weathers rather than the face
Frequently asked
Why is my garden wall leaning?
Usually foundation movement, a wall built too thin or too tall for its piers, or water saturating the brickwork because there is no coping. A leaning wall is a structural issue, not a cosmetic one — it should be looked at rather than repointed.
Do I need planning permission for a garden wall?
Generally not below two metres, or one metre where the wall adjoins a highway used by vehicles, but listed buildings and conservation areas have their own rules. Check with your council before building.