Order Line 0330 123 4123
Order Line 0330 123 4123
|Tool List || ||Safety equipment |
If the wall is part of a wider scheme, draw a scale plan. Mark in the walls of the house or large trees, and plan in all cabling and drain runs, which will need to be in position, underground and protected before starting.
Lay out the site
Transfer your plans into a full-size layout on the site, setting out with string lines and pegs. Wherever possible, plan the area so that you use full-size blocks or bricks to keep cutting to a minimum.
Use the right tools
If you will be cutting lots of bricks or blocks, use a 230mm disc grinder. Otherwise, you can use a lump hammer and bolster chisel. You will also need a spirit level at least 600mm long. See our full tool list (left).
When determining how many bricks are required, first work out the brickwork area.
For a single skin wall – also known as a half brick wall (see Fig. 1 on page 2), allow 60 bricks per square metre. This style is known as stretcher bond with only the long ‘stretcher’ faces of the bricks visible.
For a one brick thick solid wall with the visible ends of bricks known as headers on show (see Fig. 2) – allow for 120 bricks per square metre.
Laying bricks and blocks is not complicated but it does take practice to get a neat finish.
|Fig. 3 Calculate the bricks, blocks and mortar|
|Fig. 4 Mortar mixes for brickwork, blockwork & rendering (All ratios by volume)|
|Fig. 5 Calculate the number of bags of concrete mix required|
These pictures show the best ways to construct a wall, depending on the landscape in which you are working.
Fig.6 shows a simple wall or an edging to a path. Fig. 7 shows the layout of a wall with soil behind for plants, then paving. The foundations for the two walls are separate to allow drainage through to the ground below.
Fig. 10 shows how to deal with ground sloping towards the house.
Plan to lay foundations during a dry spell, and avoid working with concrete if frost is predicted.
1. Measure up for foundations
Unless you are building on to existing concrete, you will need to provide adequate concrete foundations for the wall. The foundations should be 300mm wide and 225mm deep. The bricks or blocks will be laid along the centre of the concrete surface.
2. Dig out the trench
Use pegs and a string line to mark out the trench. Excavate a 300mm deep trench where the wall is to be.
3. Drive in pegs
Drive 450mm timber pegs into the centre of the trench at 1200mm to 1800mm intervals so that they finish about 25mm below ground level. Use a spirit level and straight-edge to ensure the tops of the pegs are level. They will serve as a guide when the concrete is laid, indicating the surface level.
4. Infill the trench
Pour the concrete up to peg level (see Fig. 11), tamping it level with the edge of a board, using the tops of the pegs as a guide. Leave the concrete to cure for at least 24 hours, covering it with polythene sheeting to keep any rain off, and also to prevent it drying out too quickly in hot weather.
If this is the first time you have attempted to work with bricks or blocks and mortar, give yourself plenty of time to complete the job – and to finish the pointing neatly.
1. Mark out the wall’s position
Stretch a string line along the set concrete where the front edge of the wall is to finish. This will ensure that the first course is laid straight.
2. Mix your mortar
A good, general-purpose bricklaying/ blocklaying mortar is made with six parts sand to one part cement to one part hydrated lime (or, one bag of sand, mixed with one shovelful of cement and one shovelful of hydrated lime), plus mortar plasticiser in the mixing water.
For very hard materials, such as engineering bricks, especially in an exposed position such as a garden wall, a harder mortar mix is needed: four parts sand to one part cement with no hydrated lime. If mixing mortar by hand, mix the dry materials thoroughly together first on a board. Then make a well in the middle, add some water, and mix in. Do not add too much water. The plasticiser helps the mortar to flow without making it too wet, and the more you mix, the more it will flow. Use a shovel for mixing, not a garden spade.
You should be able to push or tap a block or brick down to create a 10mm mortar bed; if this is too much like hard work, you are probably using too much mortar or mortar that is too dry.
6. Cut blocks or bricks to fit
To cut a block or brick, chip a groove all round the block or brick along the intended cutting line with a bolster chisel and lump hammer. Lay the scored block or brick on a sand bed, place the chisel in the groove then strike firmly with the lump hammer to split the block or brick. Or, use a disc grinder.
7. Lay the second course onwards
Continue building course by course, checking the blocks or bricks are level and in line both vertically and horizontally, keeping the mortar joints to an even 10mm thickness.
If in doubt, make mortar mixes weaker rather than stronger. This is especially important when repairing or repointing older brickwork. Pre-1939 brickwork was usually built with sand and lime mortar (no cement). Re-pointing it using a strong cement-based mortar can damage it quickly, with the faces of the bricks blown off by movement and frost damage.