Building a Brick Garden Wall
The following example illustrates how to build a brick wall suitable for a garden or outdoor setting. Whilst it may be fairly straightforward for an advanced bricklayer, building a brick garden wall offers a reasonably challenging project for the home handyperson. Providing a few basic guidelines are followed, the wall will be strong and stable, and can be an attractive addition to a property.
- The wall should have reinforced concrete footings and support piers to give extra stability.
- Walls should be built no taller than a maximum height of 1.8 metres. The higher the wall, the larger the support piers need to be.
- If the wall is higher than 1 m, double bricks and support piers should be used.
- You should check with your local council about any requirements they may have regarding wall height, materials, footing depths, permits, etc.
How to Build a Brick (or Block) Wall
1. First, prepare the site
Measure the site and mark out the corners of the trench. Put wooden pegs into the ground at each corner. Make up some timber profiles 1 m beyond the outer edge of the foundation trench. This will keep the string line out of the way when attached. Next, attach string lines to each profile to indicate the width of the wall and trench.
2. Construct the concrete footings
Dig out the required area:
- For a free standing wall the footing should be 100 mm deep by 300 mm wide.
Otherwise, you can work on the basis of:
- Depth of footing = thickness of wall
- Width of footing = 2 x thickness of wall; or thickness of wall + 300 mm (whichever is greater)
Determine levels with a string line and level. On sloping ground, steps need to be created in the footing so that the wall maintains an even height.
Install timber form work to support the concrete while it sets.
Place steel rods or mesh fabric in the trench to give the concrete rigidity and strength. The mesh is supported by plastic “chairs”, concrete blocks or steel supports and these should be laid in place before the concrete is poured. Usually, one support per linear metre is sufficient.
Pour the concrete - 1 part cement: 2 parts sand: 4 parts gravel. Spread the concrete within the form work and level it off to 100 mm below ground level. Smooth it off with a wooden or steel float.
Cover the footing with plastic sheeting and leave it to cure for 7 days.
3. Lay the bricks
Stretcher bond is a commonly used pattern for single brick walls. This involves staggering the vertical joints by half a brick for each layer. For double brick walls, a header course every three to five courses gives added strength (e.g. English garden wall bond). On smaller walls a header course laid as the top course (soldier course or capping) gives a similar effect.
All courses and vertical joints should be separated by 10 mm of mortar. The mortar can be made from 1 part cement: 6 parts sand: 1 part lime. This mix is more workable and makes the mortar soft and pliable. However, it will only last a maximum of one and half hours (depending on how hot and dry the weather is), after which time it loses its elasticity and should be thrown out.
Depending how many people are working on the job, the mortar can be mixed by hand in a wheelbarrow or on the ground on a sheet of board, or mechanically mixed in a cement mixer. After mixing, it is transferred onto a mortar board to make it easier to pick up with a brick trowel.
- Calculate how many bricks you need for the wall. You will need about 50 bricks per square metre of wall face for a single brick wall.
- Place string lines as a guide to positioning your bricks.
- Start laying bricks at the lowest point and always construct the corners first.
- Set out the first row with a 10 mm gap between each brick. Mark out the line of the wall and the position of the gaps on the footing, with a carpenter’s pencil.
- Lay out a line of mortar three bricks long and place the bricks on the mortar according to the pencil marks. The mortar sets quickly so only lay three bricks at a time. Use the trowel to tap the bricks into place, making sure that they are aligned and the bed joint thickness is about 10 mm. Remove excess mortar from the bed joint with the trowel.
- Cover the end joints of the second and third bricks with mortar, and push them together slightly to ensure a good joint. Make sure the bricks are level and straight using a spirit level, and the string lines.
- Take the corners up six courses and check the alignment with a straight piece of timber. As you work, make sure the bed and cross joints are even and that the bricks are aligned and level.
- Lay one course, from corner to corner, before moving up to the next course. Always keep the corners built up higher than the rest of the brickwork and continue checking that the courses are level.
- Finish off the mortar joints while the mortar is still wet using a trowel for flush joints or a jointing tool (jointing bar) for raked and ironed (indented) joints. Use the bar or pointing trowel to smooth out the vertical joints first, then do the horizontal ones and ensure all gaps in the mortar are filled. On the end of the wall run the jointing bar first one way across the horizontal joints (adding mortar as needed), and then the opposite way.
- Lay a header row as a capping on the top of the wall. This stops water penetrating into the wall.
- Clean the brickwork with a stiff brush to remove any mortar off the brick faces.
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