Lintel
Plain English. Practical detail. UK context.
A lintel is a structural member spanning an opening such as a door or window and supporting loads above it. It may be made from steel, reinforced concrete, masonry or timber depending on the building. A lintel must be selected for the actual opening and loading, not merely for a familiar window width.
Last reviewed: (editorial review against the public sources listed below).
What needs to be known before selection
The designer needs to understand the wall construction, clear span, available bearing, masonry above and any roof or floor loads. A cavity wall may need support to two leaves and insulation detailing; a single-leaf opening has different requirements. Concentrated loads near the opening can be decisive. Existing cracks or movement also need assessment. A merchant’s product table helps select within its stated assumptions, but it cannot replace missing information about the structure.
How it is used on a job
For a new opening in a load-bearing wall, the sequence and temporary support are as important as the finished lintel. Competent design and suitable temporary works are needed before masonry is removed. The builder should coordinate bearings, any padstones, cavity tray, weep paths, corrosion protection and surrounding masonry. Building control may need to inspect at agreed stages before work is covered. Photographs and the specified product reference help record what was actually installed.
Common mistakes
Do not assume every lintel needs an identical bearing length or that a standard cavity lintel can carry any floor arrangement. Do not cut, drill or weld a proprietary steel lintel without the manufacturer’s permission and structural assessment. A decorative timber above a fireplace may not be the main support. Equally, a crack over a window does not prove lintel failure without investigation: movement, inadequate support and other defects can produce similar visible symptoms.
Alternatives and applicable guidance
A steel beam with a designed connection arrangement may be appropriate for a larger opening; an arch is a different structural form and needs its own assessment. Approved Document A provides guidance on structure in England. Wales, Scotland and Northern Ireland have their own applicable documents and procedures. Relevant product standards include BS EN 845-2 for lintels within its scope. Party wall procedures or heritage consent may also apply, depending on the location and building. Resolve these questions before ordering or demolition.
A useful question for the designer
Ask where the loads on the lintel come from and which drawing shows the support and bearing detail. Avoid treating a commonly quoted bearing length as a universal minimum that overrides the product design. If site dimensions differ from the survey, obtain a revised decision before installation rather than trimming components to fit.
Frequently asked questions
Can I choose a lintel from opening width alone?
No. Loads, wall type, bearing and the product’s design assumptions also matter.
Does a non-load-bearing partition need a structural lintel?
The support detail depends on the actual construction. Establish what the wall supports before deciding it is non-load-bearing.
Can a builder enlarge an opening before the design is ready?
That risks instability. Design, support and required approvals should be resolved first.
Is a lintel just a small steel beam?
Not necessarily. Lintels can use different materials and profiles. The correct choice depends on loads, opening size, wall construction and the surrounding details.
Sources and further reading
Public sources and further reading. Sources checked: 8 November 2026. Consult the original for details and later changes.