[edit] Setting out a Quoin (Corner)

With the foundations laid, the following simple setting out procedure must be carried out before construction of the quoin begins.

1. Set up two upright pegs at each corner of the foundations. Stretch twine between them along both the front and side of the proposed structure (fig. 1 below).

2. Check that the corner angle is square using either the 3-4-5 method or a builder's square (figs. 2 and 3 below).

3. In the corner of the foundation, lay down a screed (thin layer) of wet mortar, extending about 600mm along the foundation (fig. 4 below).

4. Hold the spirit level vertically against the string (without bending it) and score a line with the trowel where the bottom of the spirit level touches the screed (fig. 5 below). The mark must be directly under the string. Repeat this about 500mm along the screed and using a straight edge join up the two marks (fig. 6 below). Do the same along the side of the foundation so that both the building lines have been transferred down from the twine to the concrete.

5. The upright pegs and twine can now be removed so that they do not interfere with the bricklaying.

6. Lay the bricks 'dry' outside the line of the main wall, following, your chosen bonding arrangement.

The idea is to adjust the width of the vertical joints, or perpends, between the bricks to achieve the best layout,that is until there are just a small number of cut bricks or better still none at all. A cut brick in the wall is a weak point and too many will destroy the bond altogether.

This complete setting out procedure must be carried out for each corner of your proposed project. You are then ready to start building your quoin.

1 Bang two pegs firmly into the ground at each corner of the foundations. The twine stretched between the pegs must be taut

2 When the twine is in place, check that the angle between the two lines is square with a builder's square

3 Another way to check for square is by geometry. If two sides of the triangle measure 3 units and 4 units the diagonal must measure 5 units

4 Directly under the twine, at each corner, lay down a thin screed of wet mortar extending about 600mm along the foundations

5 Carefully hold a spirit level against the twine, check that it is plumb, then score a line where its base touches the screed

6 Join up the scored fines at both the front and side edges. Once the pegs and twine are out of the way, these provide the building line

[edit] Building a Quoin

• Lay down a mortar bed inside the scored line, taking care not to cover it (fig. 7 below).
• Carefully lay the first three bricks from your dry run along the mortar joint, keeping the face of the bricks aligned with the scored line of the foundation (fig. 8 below).
• Using the spirit level, check these bricks for horizontal (fig. 9 below) and then lay the remaining bricks forming the first course of the quoin.
• Repeat this procedure down the side of the corner to form a right angle. The corner is then described as being 'set out' (fig. 10 below).

[edit] Racking Back

You can now continue building up the quoin following your chosen bond. Shorten each course after the first one so that you 'rack back' the quoin to eventually end in a single brick (fig. 11 below).

As you build, constantly check the quoin for plumb, line and level using your spirit level (fig. 10 below). You must also check the width of the horizontal, or cross, mortar joints, (fig. 11 below) Do this with a gauging rod, a straight piece of wood marked off at intervals which correspond to the height of a brick and one mortar joint.

A final check across the diagonal racking back with a spirit level (fig. 12 below) should confirm that the quoin is properly aligned. When all the quoins of your proposed structure have been completed, you can fill in the intervening walls.

7 Care fully lay down a mortar bed, in preparation for laying the first bricks. Take care not to cover the building line

8 Promptly, but carefully, lay the first three bricks. Align the face of each with the scored line on the foundations

9 Only when these bricks have been checked for level should the remaining bricks of the quoin's first course be laid down

10 The side bricks of the quoin can now be laid, using the spirit level on end to check that all the bricks are in line and level

11 Each course after the first should be shortened by one brick and the quoin built up so that it ends in a single brick on top

12 At this stage, the racking back of the quoin should be checked a long its diagonal edge to ensure that the structure is level

[edit] Building Intervening Walls

To build the intervening wall between two quoins, you need a set of mason's lines and blocks (fig. G). The tension on the line between the blocks holds them in position. The line should be in the same place as the proposed mortar joint and act as a guideline between the quoins. With this in place you can build up the wall following your chosen bond.

On very long walls, the line may tend to sag in the middle, In this case. you need a tingle, a piece of metal supported on 'dry' bricks (fig. below) to support it in the middle.