What is a brick bond, and which one should I use?

Bond is not decoration, though it looks like it. Its structural job is to make sure that no vertical joint in one course sits directly above a vertical joint in the course below, because a continuous vertical joint is a line the wall can split along. Everything else about bonds — the patterns, the names, the regional preferences — follows from that one requirement. The drawing sets the four common bonds side by side and shows how to read a wall's construction from the pattern.

Step by step

1. Learn the two words that make everything else make sense.A stretcher is a brick laid with its long face showing. A header is a brick laid with its short end showing. Every bond is a pattern of stretchers and headers, and where you see headers, bricks are running through the thickness of the wall.
2. Recognise stretcher bond.Every brick a stretcher, each course offset half a brick from the one below. It is a half-brick-thick skin. On a house this is almost always the outer leaf of a cavity wall; on a garden it is a single-skin wall. It is the commonest bond in modern Britain by an enormous margin.
3. Recognise English bond.Whole courses of stretchers alternating with whole courses of headers. The headers tie the two skins of a one-brick solid wall together, and it is the strongest of the traditional bonds. Common in engineering work, retaining walls and older utilitarian buildings.
4. Recognise Flemish bond.Stretchers and headers alternating within each course, with a header centred over each stretcher below. Also a solid one-brick wall. Generally considered better looking than English bond and very widespread on Georgian and Victorian frontages.
5. Recognise header bond and the garden wall bonds.Header bond, all ends showing, is used on tight curves and as a decorative panel. English garden wall and Flemish garden wall bonds insert extra courses of stretchers to reduce the number of headers, which is cheaper and easier and still ties the wall.
6. Use the bond to read the wall.Headers in the pattern normally mean a solid wall one brick thick. All stretchers usually means a cavity wall or a single skin. This is the quickest exterior test there is for whether a house is solid-walled, and it feeds directly into decisions about insulation, damp, pointing and render.
7. Treat that reading as evidence, not proof.Snapped headers — half bricks laid to show an end — are sometimes built into a cavity wall's outer leaf purely to imitate a solid bond, especially on estates designed to look older than they are. Confirm by measuring the wall thickness at a window or door reveal.
8. Choose stretcher bond for a single-skin garden wall.For a low half-brick garden wall it is the only sensible option. Bring in piers at intervals for stability, and cap it with a coping that oversails both faces.
9. Match the existing bond when extending or repairing.A patch in a different bond is more visible than a patch in a different colour. Copy what is there, including the pattern of any snapped headers.
10. Set out dry before you build.Lay the first course out dry along the foundation, with the joints spaced, before you mix any mortar. It tells you where the cuts fall, whether the length works out, and how to arrange the bond around openings and returns.

Tips

• A soldier course — bricks stood on end above a window or a door — is a decorative detail, not usually the structure. There is normally a steel or concrete lintel behind it doing the work.
• The vertical joints are called perpends, and keeping them plumb one above the other in alternate courses is what makes a wall look properly built. It is the detail that separates good brickwork from adequate brickwork.
• Regional bonds and regional brick sizes go together. If you are matching an older building, look at what the neighbouring houses of the same date do.

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