When a hole is made in a wall, the bricks above lose their support. The lintel bridges the opening and rests on the wall on either side. It is usually reinforced concrete, cast in place or precast, and in some cases steel.
In a new opening in an infill wallInfill wallA brick wall that fills the gap between columns, beams and slabs. It divides rooms, but it isn't built to hold the building up., the lintel goes in before or as the bricks come out, so the wall above doesn't sag or crackCrackA split or gap in render, concrete, a wall, a coating or wood. Fine cracks are usually only on the surface; ones that grow, keep reopening or run diagonally need attention.. It needs a good bearing on each side of the opening.
In a load-bearing wallLoad-bearing wallA wall that carries part of the building's weight, such as floors, beams or the storeys above. It must not be removed or opened up without an engineer's design and the required permit. a lintel is no simple matter: its size and construction come from an engineer's structural designStructural designAn engineer's study that checks whether a building can take a change, such as an opening in a load-bearing wall, and sets out how it is done and how it is strengthened.. Diagonal cracks running from the corners of a door or window are worth having a specialist look at.
Related terms
Infill wallInfill wallA brick wall that fills the gap between columns, beams and slabs. It divides rooms, but it isn't built to hold the building up.Load-bearing wallLoad-bearing wallA wall that carries part of the building's weight, such as floors, beams or the storeys above. It must not be removed or opened up without an engineer's design and the required permit.Structural designStructural designAn engineer's study that checks whether a building can take a change, such as an opening in a load-bearing wall, and sets out how it is done and how it is strengthened.