How to plan a garden wall

A garden wall in brick or stone may be more expensive than a fence, but it'll weather attractively and last a lifetime. You'll need planning permission for any wall over 1 metre high on the edge of a public highway, and for any free-standing wall over 2 metres high. You may well need a structural engineer's specification for large retaining walls - but you shouldn't really be attempting these anyway without some experience on less ambitious building projects.

Although the techniques for building a wall are pretty straightforward, you'll need to plan and design it properly if it's to be strong and stable. The design of your wall will depend to a large extent on what you're using it for.

How to plan a garden wall

Garden walls have lots of uses, such as:

  • Holding earth back so you can create a terraced area, or stop a steeply sloping bank from collapsing.
  • Creating a solid barrier next to a road or footpath to reduce noise, or for privacy.
  • To divide a garden into different areas, or provide extra seating around a feature like a terrace or pond.
  • To provide a low, solid base on which you can put up fencing, or build piers to support an overhead structure such as a pergola.

You can build a garden wall from bricks, natural stone or reconstituted stone. There's a wide range of reconstituted stone on the market, made from concrete blocks that are finished and coloured to look like stone.

How to plan a garden wall

Brick walls

Bricks are the cheapest material and come in a range of colours, depending on the type of clay they're made from and the manufacturing process. They can also be multi-coloured or mottled, and have a rough or smooth texture. Second-hand bricks often have a weathered look that blends in with old house walls, but they're not cheap - and there's usually no way of telling if they're frost-resistant.

How to plan a garden wall

Natural stone walls

You can buy natural stone from quarries or reclamation yards, but it's very expensive. The stone you buy in its natural state is called random rubble or undressed stone. Semi-dressed stone is cut into fairly uniform blocks with uneven surfaces, while fully-dressed stone with machine-cut faces is called Ashlar. The wall shown here is built with semi-dressed stone.

How to plan a garden wall

Semi-dry stone walls

A genuine dry-stone wall is built from stones that are carefully chosen so they're perfectly stable without needing mortar to bind them together. This wall is a semi-dry stone wall. It looks like a true dry-stone wall, but has hidden mortar joints.

How to plan a garden wall

Dry-stone effect walls

These walls are made from reconstituted stone blocks that let you create the look of a dry-stone wall at a fraction of the cost of the real thing.




A brick wall is made of layers of bricks (known as 'courses') cemented together with mortar. The pattern in which the bricks are built is called the 'bond'. The idea of a bond is to stagger the vertical mortar joints so they're not in the same place in two or more consecutive courses. This spreads the wall's load along its length, which makes it stronger and more stable.

The three types of bond most often used for garden walls are stretcher bonds, English bonds and Flemish bonds. When you're working out the number of bricks you'll need for a particular bond, add an extra 5% to allow for cutting bricks and breakages.

How to plan a garden wall

English bond

You can form this pattern by laying alternate courses of stretchers and headers. Insert queen closers before the last header to maintain staggered joints at the ends of your wall, and at right-angled corners. You'll need approximately 120 bricks per square metre.

How to plan a garden wall

Flemish bond

Headers and pairs of parallel stretchers alternate on each course to make a double-skin wall. Use queen closers on alternate courses to stagger the joints. You'll need approximately 120 bricks per sq m.

How to plan a garden wall

Stretcher bond

You should use this type of bond for single-skin walls the thickness of a single brick, and double-skin walls when they're joined with wall ties. Lay all the bricks lengthways with the long face exposed. Half-bricks (half-bats) complete the end of every other course on a straight wall, so that each vertical joint centres on the bricks above and below. And to make corners, just alternate headers and stretchers. You'll need approximately 60 bricks per square metre.


General-purpose mortar (moderate conditions) 1 part cement
1 part lime
6 parts soft sand
Strong mortar (severe conditions) 1 part cement6 parts soft sand plasticiser
Very strong mortar (exposed to snow, heavy wind and rain) 1 part cement
4 parts soft sand
plasticiser

 

Storing materials

Keep your bricks and mortar materials dry until you're ready to use them. It's a good idea to cover bricks, sand and aggregate with a plastic sheet. Also, try to raise bags of cement off the ground and cover them with a plastic sheet, or store them indoors.

 

Gauging mortar

For most purposes, you can measure mortar ingredients with a shovel. But on some types of wall (such as faced brick or pointed stonework) it'll spoil the finish if the mortar varies in colour. 'Gauging' the mortar stops this from happening - as you measure the proportions of the mix more precisely, using a bucket rather than just a shovel. Draw a line on the inside of a bucket with a felt-tip marker indicating one unit of the mix. Then shovel the ingredients in turn into the bucket, making sure each measure is level with the line.