How to choose a lintel

What a lintel does

A lintel carries the masonry above a door or window opening and passes the load down into the wall at each side. Choosing the wrong one can lead to cracking or failure, so the details matter.

Steel or concrete?

Steel lintels are light, come in shapes to suit cavity walls, single skins and timber frame, and are the usual choice for cavity walls. Prestressed concrete lintels are heavy and robust, and are commonly used in solid walls and internal block walls.

What to check before ordering

• Wall type: cavity wall, solid wall, single leaf or timber frame.
• Cavity width, for cavity lintels, measured between the two leaves.
• Clear opening width, plus the bearing needed at each end (often at least 150 mm each side) to give the lintel length.
• Inner and outer leaf thicknesses.
• The load above: masonry only, or floors and roof bearing on the wall too.

When to ask an engineer

Standard domestic openings can often use a lintel picked from the manufacturer's load tables. Wide openings, openings under concentrated loads, or anything you are unsure about should be checked by a structural engineer or building control.