Horizontal beam to carry a wall over a door or window opening. When formed of reinforced concrete they are usually pre-cast but over wide openings may be cast in-situ. For cavity walls, in facing bricks, a Boot Lintel (section resembles a boot) is used to close both the internal and external walls and the toe of the boot carries the external wall. There are now available a number of manufactured pre-formed galvanised steel boot lintels that also act as a cavity tray to prevent moisture from entering the building; they have the advantage that the thin metal toe does not mar the appearance of the face work.