What is a flat course?
A flat course is a course of brickwork in which the bricks lie flat on their bed face but are turned so that the header (the short end) faces outwards. It is the lying counterpart of a brick-on-edge course, where the bricks stand on their edge or end.
You mainly meet it where a wall is closed off or an opening is bridged: on top of a garden wall, under a window sill, above a window or door opening and as the finish to a parapet.
Flat course or brick-on-edge?
Both do the same job — close a wall neatly or bridge an opening — but look and behave differently:
- The brick-on-edge course stands upright. That gives a tall, narrow band with many joints and a strongly vertical rhythm.
- The flat course stays low and wide. There are fewer joints per metre run and the band reads more quietly. Because the bricks lie flat, it bonds more comfortably with the normal brickwork below it.
Above an opening, a flat course does not really carry: like a soldier arch, it needs a lintel or steel angle to bear on once the span grows. Treat the course as a finish, not as structure.
Execution — where it goes wrong
- Shedding water. A flat course on top of a wall sits level and therefore holds water. Provide a fall, an overhanging edge, or better still a proper coping of stone, concrete or metal above it.
- Frost resistance. The course is exposed on every face. Use hard, frost-resistant bricks (engineering or well-fired facing bricks) and a mortar suited to that exposure.
- Setting out. Divide the headers along the length in advance so you do not finish with a sliver of a cut brick in the corner. Dry-lay the course before you bed it.
- Jointing. Full, well ironed joints. Hollow or over-dry joints here are the fastest route to frost damage.
Related terms
- Brick-on-edge course
- Header course
- Lintel
- Masonry mortar
- Frost resistance
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