Brickwork and Garden Paving
Brickwork and Garden Paving
Laying paving and building with bricks or blocks are skills which are easily mastered, but before you start to lay bricks, be sure that you can use a trowel correctly. Wherever you work with mortar, you will need this tool to butter the ends of bricks, and to make sure that they are laid evenly. Having done this, you will simply need to follow the basic principles and ensure that your work is square, level and plumb..
Mortar is a material used in all bricklaying and some types of paving. Made from cement, sand and in some instances lime, it is mixed in the same way as concrete. First combine the dry materials on a clean, flat surface or in a wheelbarrow, then add water to them. Aim for a mixture which is thick and smooth but not watery, and only mix as much as you can use in a couple of hours. If the mortar gets hard, throw it away; adding water will weaken the mixture.
Bricklaying is one of those skills which improve with practice. The more bricks you lay, the easier it becomes. Whatever you are building, the techniques are exactly the same.
The first course, of all walls (including the risers of steps), and most edgings around patios are bedded in wet mortar. Start by laying a ‘sausage’ of the mixture along the line where the bricks are to be laid. Use a bricklayer’s trowel to create a furrow through the middle of the mortar, and place the first brick in position. The end of the next and subsequent bricks may be buttered, or you can use a trowel to fill in the gaps (which should be about 10mm thick) once the bricks are in place on the bed of mortar. Use a spirit level to make sure that the first course is level; if bricks are not properly aligned, tap them firmly with the handle of the trowel. If necessary, lift the bricks and add or remove mortar.
The next course is laid in the same way, with a 10mm wide joint and mortar separating the bricks. Stringing a builder’s line along each course will help to keep the wall straight. You can keep the line in place with metal pegs, or wrap a builders’ line around a pair of corner blocks (L-shaped blocks of wood with a slot and groove cut in each to accommodate the string) and hook the blocks onto the corners of the brickwork with the builders’ line pulled taut.
An essential principle of good brickwork is bonding. If a wall or riser is laid so that the bricks don’t bond and form a solid mass with an evenly distributed load, it will lack strength and stability. There are several different types, the most common being stretcher bond, where each brick overlaps the two below it by half.
Paving must always be laid so that the water drains off it effectively. This means that in most cases you will aim for an even slope with a gradient of no more than 1:40. In many instances, you will need to include some type of edging restraint.
The material chosen for your paved surface will to a large extent determine how it is laid. The basic choice is between setting slabs, bricks or blocks on a bed of sand and setting them in mortar. If bricks are used, they may be laid in any number of patterns, some of which bond particularly well and are therefore popular for driveways and surfaces intended for heavy foot traffic. A running bond (which is the horizontal equivalent of stretcher bond) is fairly common, as are both basketweave and herringbone patterns.
The simplest and least expensive form of brick paving is laid on sand. Known as flexible paving, it requires no mortar except for the edging, and sand is brushed into the joints. However, some people do lay bricks on sand and then brush either a very weak mixture of dry cement and sand or a slightly crumbly, moist mixture between the joints, then spray the surface with water.
Rigid paving is more time-consuming, and because mortar is required it is also more costly. However, this method is preferred for steps, as it is more stable. There are various methods of laying rigid paving, although all involve setting the bricks on a mortar bed. You can either butter the ends of the bricks as you lay them in place, or fill the joints later by brushing a dry cement and sand mix over them and then spraying the entire surface with water.