Setting out
Lintel overall length
- where
- overall lintel length (mm)
- clear opening (mm)
- left end bearing (mm)
- right end bearing (mm)
Explain this equation
This adds the end bearings to a clear opening to give the overall length of lintel required.
W is the clear width of the opening in mm. b_L and b_R are the bearings at the left and right ends: the length of lintel that sits on the masonry each side. L_lintel is the overall length.
The lintel spans the opening and rests on the wall at both ends, so its total length is the opening plus both bearings. There are no factors; all values are in millimetres.
A 1200 mm opening with 150 mm bearings each end needs a 1500 mm lintel. Lintels come in standard lengths, so you will usually pick the next size up.
Watch out: this is length only. Bearing lengths, lintel type and load capacity come from the design and the manufacturer.
Add the designer’s end bearings to a clear opening.
Enter your values to see the result.
Good to know
Length arithmetic only. Does not select a lintel, bearing, padstone, cavity tray or load capacity. Use approved drawings and manufacturer requirements.
Sources
- Geometry / arithmetic
Estimates are not design approval or British Standards compliance checks. Structural arch, retaining-wall, wind, foundation, lintel and masonry-capacity design are not performed. Use the project engineer’s specification.