Building a Garden Wall

A garden wall is a whole masonry project in miniature: it has foundations, a damp-proof course, bonding, movement joints and a weathering detail on top, and it fails in exactly the same ways a house wall does when any of them is skipped. It is also one of the few walls you can legally build without any approval at all, provided it stays within the permitted development limits.

This page is a working template for the whole job: the task order, what you will be ordering, the height and boundary rules, and the calculator that serves each step. The two things that most often go wrong are decided before the first brick: a foundation too shallow for the ground, and a wall started before anyone checked the height rules for its position.

Work in this order

1. 1

   Check the rules before you order a brick

   Walls, fences and gates have height limits under permitted development, and the limit is lower where the wall fronts a highway: check your case with the Fence Height Calculator (it covers walls) or read the quick answer on maximum fence and wall heights. Conservation areas and listed buildings change the picture. If the wall sits on or at a shared boundary, check the Party Wall Checker before starting.

2. 2

   Set out and dig the foundation trench

   Check for underground services before digging, then set the wall line out with pegs and string. The trench is wider than the wall and its depth depends on the wall height and the ground: clay soils need deeper foundations to avoid heave. Size the concrete with the Foundation Calculator, and the dig itself with the Groundwork Excavation Calculator.

3. 3

   Pour the concrete and let it cure

   The foundation is poured, levelled and left to cure before any bricks are laid on it. Mix quantities come from the Concrete Mix Calculator, with the method in our guide to mixing concrete and the standard mixes in the Concrete Mix Ratios reference.

4. 4

   Dry-lay the first course, then bed the DPC in

   Laying the first course without mortar shows you the spacing and any cuts before you commit. A damp-proof course goes in low in the wall, above finished ground level, to stop moisture rising through the masonry: quantities from the DPC Calculator, materials in the UK DPC Specifications reference, and the concept in the glossary.

5. 5

   Corners first, then fill between, in steady lifts

   Corners are built up first and checked for plumb, then a line is stretched between them and each course is laid to the line with consistent joints. Do not race the mortar: too many courses in one session squeezes the joints before they have stiffened. Quantities come from the Brick Calculator or Block Calculator plus the Mortar Calculator. Freestanding walls of any length or height gain stiffness from piers: the Brick Pier Calculator covers them, and the Brick Boundary Wall Calculator quantifies the whole wall, piers and copings together.

6. 6

   Movement joints on long runs

   Masonry moves with temperature and moisture, and long unbroken runs will crack without joints to absorb it. Position them with the Movement Joint Calculator, with the spacing rules in the Movement Joint Spacing reference.

7. 7

   Point the joints, then cap the wall

   Joints are finished when the mortar is thumbprint-hard, and the wall is capped with copings that overhang and shed water: an uncapped wall top soaks up rain and suffers frost damage. The Brick Boundary Wall Calculator includes coping quantities, the pointing glossary entry covers the joint profiles, and the full method is in our step-by-step garden wall guide.

What you will be ordering

Below ground: foundation concrete, either site-mixed from cement, sand and aggregate or delivered ready-mixed. In the wall: facing bricks or concrete blocks (ordered with a margin for cuts and breakages, from one batch so the colour matches), cement and building sand for the mortar with a plasticiser, and a roll of damp-proof course the width of the wall.

On top and in between: coping stones or capping to finish the wall, and movement joint filler and sealant for long runs. The Brick Boundary Wall Calculator quantifies most of this in one pass; the individual calculators above cover each material separately.

The rules that touch a garden wall

Every calculator, by job stage