Once you have learned how to lay bricks quickly and accurately , the next stage of bricklaying is to become familiar with the various patterns—or bonds—in which bricks are laid. At the same time, you will come across quite a few bricklaying terms: it is important to learn these, as they crop up time and time again.
In bricklaying, bricks cut to different sizes are all given different names. Cut in half across its width, a brick becomes a half-bat. Cut to three-quarters of its length, it becomes a three-quarter bat and to a quarter of its length, a quarter-bat. A brick cut in half along its length is known as a queen closer. This is used for building strengthened corners, or quoins.
The way in which bricks are laid also has its own terminology. A brick laid so that one of its longest sides is visible in the finished wall is known as a stretcher. If it is laid so that one of the ends shows, it becomes a header.
All bricks conform to a specified arrangement to ensure maximum strength, load-bearing property and a uniform appearance. This arrangement is called a bond.
As a general rule, no brick should be laid directly on top of another: instead, it should overlap the joints between the bricks above and below it so that there are no straight joints running up the wall. The various bonding patterns in use all follow this rule and ensure that the vertical joints between bricks are staggered over the whole wall. Stretcher bond : This is the simplest of all bonds. It is used in walls which are half a brick thick—the minimum thickness of any brick wall. Each brick overlaps the one above and the one below it by half a brick’s length to provide a simple, strong bond which involves cutting half-bricks only at the ends of courses. About 50 bricks are needed for each 1m2 of brickwork.
English bond: This bond makes a wall one whole brick thick. The strongest of all bonds, it is used wherever high load-bearing qualities are called for—such as foundations and man-holes. About 100 bricks are needed for each 1m2 of brickwork. It consists of alternate rows, or courses, of headers and stretchers.
As the bricks overlap by only a quarter of a brick’s length , care must be taken to keep the perpendicular joints aligned and staggered on each alternate course. Otherwise the bond tends to ‘creep’ as the courses progress and form straight joints where a crack may appear when stress is applied.
To keep the bond aligned at its corners, a queen closer is laid end-on next to the corner brick.
Flemish bond: This bond also makes a wall one whole brick thick. But because it has numerous internal straight joints, it is not as strong as English bond and is used more in decorative work, such as garden walls. When British houses had solid 9 inch brick walls instead of cavity walls, it was the bond most used to build them.
Flemish bond consists of alternate headers and stretchers along a single course. Each stretcher has a header above and below it forming what is called the ‘Flemish star’ and the decorative properties of the bond are accentuated if this is laid in different coloured bricks.
This bond takes a long time to build and also has a tendency to creep if sufficient care is not taken in aligning the vertical joints of alternate courses. To start each course correctly, it too requires a queen closer next to each corner brick.
English garden wall bond: More complex and not as strong as standard English bond, this incorporates two overlaps—one of half a brick’s length , the other of a quarter brick’s length. It is an arrangement of three or five courses of stretchers for every course of headers. Care must be taken to ensure that the joints on the header courses align vertically.
The English garden wall bond is economical because it incorporates a lot of stretchers, so there is less wastage from cutting bricks.
American bond: This is similar to English garden wall bond, except that it has one course of headers to every five or six courses of stretchers, and— because of the deep perpendicular joints between the bricks on the face of the wall and those at the back—is correspondingly less strong. Like English garden wall bond, it is used only for decorative outdoor brickwork, not for building construction.
Flemish garden wall bond: This is a complex arrangement used in decorative brickwork and consists of three or five stretchers followed by a header repeated along the same course. The headers are arranged so that they are centred in the block of stretchers in the course above.
Open bond: This bond is purely decorative. Consisting of stretcher courses with a quarter-bat spacing , the spacing is decreased at the corners to maintain the bond. The top of the bond can be finished with either a solid course of stretchers or with a course of coping slabs.
Mortar, the material which binds bricks, is composed of a binding material—such as cement or lime— and a fine aggregate—such as sand— and water. Bricklaying sand for general use should be graded either ‘soft’ or ‘fine’ for best results.
For all mortars, the specified quantities must be mixed to correct and constant ratios over the whole of the project. Where this rule is not observed, cracking caused by uneven expansion and contraction occurs and the difference in the mortar mix shows through as colour changes in the finished work.
For general and normal house construction four parts of sand to one of cement is the correct ratio—but variations on this mix can be used according to the needs of the bond. Take advice from the brick supplier to ensure that the mortar is neither stronger nor weaker than the bricks it is being used with.
To test the water content of a mortar mix, press a trowel into it. If the impression made remains for a minute or more, the mix is of the correct consistency. If the edges around the impression crumble, the mix is too dry. If the impression fills up with water, the mixture is too wet and more cement and sand in the correct ratio should be added.
Water gives mortar its bonding power. When making up the mix, it is most important to use only fresh, clean water. Dirty water or water from a rain barrel will cause the mix to quickly break up
Many companies now are producing a form of ready-mixed mortar—gauged mortar—which is sand and lime mixed to a ratio of approximately six of sand to one of lime. As this mixture does not contain any cement, it does not set hard and will retain its water content for extended periods. The cement is added according to the manufacturer’s recommendations.
To make the mortar easier to use during bricklaying, additives called plasticizers are added. These aerate the mortar and spread the water content evenly throughout the mix, making it more malleable and easier to use for longer periods.
For non-structural brickwork, washing-up liquid makes a suitable plasticizer. For structural brickwork, a proprietary plasticizer — available cheaply from builders’ merchants— should be used. The correct quantities to use for different jobs are printed on the back of the container. Gauged mortars contain lime and do not need a plasticizer. Similarly, the masonry cement sold in the US and Canada already has a plasticizer added.
Strip foundations are very simple and are really only suitable for garden walls. Foundations for houses or garage walls are much more elaborate, and vary from area to area. In countries subjected to hard frosts in winter such as the UK and Canada, for example, they must extend at least 1200mm below ground level to avoid ‘frost heave’. Building such foundations is described later on in the course.
Setting out a quoin
With the foundations laid, the following simple setting out procedure must be carried out before construction of the quoin begins. • 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. • Check that the corner angle is square using either the 3-4-5 method or a builder’s square. • In the corner of the foundation, lay down a screed of wet mortar—extending about 600mm along the foundation. • 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. 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. 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. • The upright pegs and twine can now be removed so that they do not interfere with the bricklaying. • 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 until the wall ‘works brick’—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.
Building a quoin • Lay down a mortar joint inside the scored line, taking care not to cover it. • 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. • Using the spirit level, check these bricks for horizontal 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’.
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.
As you build, constantly check the quoin for plumb, line and level using your spirit level. You must also check the width of the horizontal, or cross, mortar joints, Do this with a gauging rod—a straight piece of wood marked off at intervals of 75mm. The 75mm corresponds to the height of a brick and one mortar joint.
A final check across the diagonal racking back with a spirit level 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.
Building intervening walls
To build the intervening wall between two quoins, you need a set of mason’s lines and blocks. 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 —to support it in the middle.
Most general building bricks are made of clay or calcium silicate. Others are made of concrete, pottery waste, clinker and even crushed and moulded cinders. This variation in brick-making methods gives rise to an enormous variety of different types of bricks, few of which will all be available in the same area.
A more convenient way to classify bricks is by use. Here, four different types can be distinguished. Common bricks: These are general-purpose bricks, used for such jobs as internal house walls and external walls which are to be rendered. Common bricks are usually roughly and unattractively finished and are also subject to frost damage. They should not be used for large areas of bare brickwork. Face bricks: More expensive than a stock brick, these are used wherever bare brickwork is to be left showing. Face bricks are available in various colours and textures, are well finished and have a fairly good resistance to water and frost. The mortar joints on face brickwork should always be finished off neatly with a pointingtool. Loadbearing bricks: These may be either face bricks or commons in appearance, but will conform to specified compression strengths and stress loadings. They are used, for example, where a load-bearing internal wall has been knocked down and brick pillars are to be erected to support the steel joist put in its place to take the load. Engineering bricks: These are the hardest bricks of all and are made of clay, burnt at high temperatures in large kilns. They are designed to carry heavy loads and can also be used where exposure to the elements is likely to be a problem. The term does not apply to calcium silicate bricks, which are hard, but may not quite reach the specified strength and compression requirements of engineering bricks.
A point to remember when stacking bricks is that they should all be stacked on edge, in opposing directions, on each alternate row. Otherwise, bricks could topple off the stack and damage their edges—expensive if the whole pile collapses.