A door lintel is the structural support installed above a doorway in a masonry wall. It carries the masonry and other loads above the opening, transferring them into the supporting wall at each end.
The correct door lintel depends on the wall construction, the width of the structural opening, the required end bearing and the loads above it. Choosing by door width alone is not enough.
Already know your wall type and opening size? Browse Wade’s door lintel selection, or use this guide to narrow down the type and size you need first.
Do I Need a Lintel Above My Door?
A doorway creates a break in a masonry wall. The load that would otherwise continue through the wall must therefore be carried across the opening and transferred into suitable masonry on either side.
The door frame itself is not normally designed to support brickwork, blockwork, floors or roof loads. Where masonry has been allowed to bear on a door frame, the frame may eventually distort, the door may begin to stick and cracking can develop around the opening.
A door lintel will commonly be required in:
- external cavity walls;
- solid brick, block or stone walls;
- loadbearing internal masonry walls;
- non-loadbearing masonry partitions;
- the external masonry leaf of timber-framed construction; and
- new or widened openings formed in existing walls.
Non-loadbearing timber and metal stud partitions are different. These normally use a timber or metal header to form the top of the door opening, rather than a structural masonry lintel.
Older properties may contain concealed steelwork, timber, stone lintels or structural brick arches. The absence of a visible modern lintel does not prove that there is no support above the doorway. Do not remove masonry until the existing construction has been properly established.
Which Type of Door Lintel Do I Need?
Wall construction is the first major decision. A lintel designed for a cavity wall is not interchangeable with one intended for a solid wall or a single masonry leaf.
External cavity wall
A steel cavity lintel can support the inner and outer masonry leaves across the opening. The profile must suit the cavity width, leaf dimensions and loading.
Check: cavity width, inner leaf, outer leaf, span and load duty
Solid masonry wall
A box lintel, solid-wall lintel or another specified steel or concrete section may be used, depending on the wall thickness and finish.
Check: total wall thickness, masonry type, finish and loading
Internal masonry wall
Concrete lintels are commonly used over internal blockwork and brickwork openings. Steel box or single-leaf lintels may also be suitable.
Check: wall width, whether it is loadbearing and the required finish
Patio or bifold opening
Wide openings can carry substantial masonry, floor and roof loads. They may require a heavy-duty lintel or a separately designed steel beam.
Check: clear span, wall construction, floor direction, roof loads and point loads
What Size Door Lintel Do I Need?
Door lintel size has two separate parts:
- Length: determined by the clear structural opening and the required end bearing.
- Section and duty: determined by the wall construction and the loads the lintel must carry.
A lintel can be long enough to bridge the doorway but still be unsuitable for the load. Length alone does not establish whether a standard, medium, heavy or extra-heavy-duty lintel is required.
- Clear structural opening
- The masonry-to-masonry width beneath the lintel
- End bearing
- The length supported by masonry at each end
- Wall construction
- Cavity, solid, single leaf, concrete block or timber frame
- Load above
- Masonry, floors, roof loads, point loads and nearby openings
How to calculate the lintel length
The basic calculation is:
Minimum lintel length = clear structural opening + bearing at the left-hand end + bearing at the right-hand end.
For example, if the selected lintel requires a 150mm bearing at each end and the structural opening is 900mm wide:
900mm + 150mm + 150mm = 1,200mm minimum lintel length.
This example must not be treated as a universal bearing rule. Many steel lintels specify a nominal 150mm bearing at each end, while some concrete lintel ranges publish different minimum bearings for smaller openings. Always use the technical data for the exact product being installed.
Measure the structural opening, not just the door
The finished door leaf is narrower than the structural opening. The opening also needs to accommodate the frame, installation gaps, packers and the tolerances specified by the doorset manufacturer.
Do not order a lintel using only the advertised door width. Establish the required masonry opening first, then calculate the lintel length from that opening.
How is the required lintel duty calculated?
The load can include more than the masonry immediately above the doorway. The specification may also need to account for:
- floor joists or concrete flooring bearing towards the opening;
- roof rafters or trusses;
- concentrated point loads;
- windows or other openings close above the door;
- insufficient masonry for normal load distribution;
- unusually wide cavities or inner leaves; and
- the condition and strength of the supporting masonry.
Duty labels are not necessarily identical between manufacturers. Check the published load table for the selected product rather than assuming that every standard-duty or heavy-duty lintel provides the same capacity.
Steel or Concrete Door Lintel?
Steel and concrete lintels can both be used above door openings. The more suitable material depends on the wall, span, loading, finish and installation requirements.
| Consideration | Steel lintel | Concrete lintel |
|---|---|---|
| Typical applications | External cavity walls, solid walls, single leaves and wider openings | Internal masonry, blockwork, solid walls and applications where the lintel may be plastered or left visible |
| Cavity-wall support | A cavity lintel can support both the inner and outer leaves | Separate lintels or another designed arrangement may be required for the two leaves |
| Handling | Often lighter than a comparable concrete section, although long or heavy-duty products still require planned handling | Can be heavy and may require additional lifting arrangements as length and section increase |
| Finish | Usually concealed within the wall and supplied with a protected finish appropriate to its specification | Can provide a suitable base for plaster or paint, with fair-faced products available for exposed work |
| Cutting | Should not be cut unless the manufacturer has expressly approved the alteration | Some ranges can be cut to length, but this must be confirmed in the exact product data |
| Specification | Profile, cavity width, leaf widths, span and load duty must all match the construction | Section size, orientation, span, bearing and published load capacity must be checked |
A concrete lintel may be an economical choice over a straightforward internal blockwork doorway. A steel cavity lintel is generally a more practical starting point where both leaves of an external cavity wall need support.
Neither material is automatically stronger or more suitable in every situation. Performance depends on the specific section, length, bearing, installation and load.
Door Lintel Installation and Regulations
The selected manufacturer’s installation instructions take priority over general guidance. Different lintel profiles may have different requirements for bearing, orientation, propping, masonry construction, damp protection and curing.
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Confirm the lintel specification
Check the product reference, wall type, cavity width, length, load duty and orientation before installation. Inspect the lintel for damage and confirm that it matches the drawing or schedule.
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Prepare the end bearings
Provide the full specified bearing at each end on sound masonry. The lintel should be fully bedded and should not rely on loose, damaged or inadequately supported masonry.
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Install the lintel level
Level the lintel along its length and across its width. Install it in the correct orientation, following any top marks, labels or profile-specific instructions.
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Build the masonry correctly
Where a steel cavity lintel supports both leaves, raise the inner and outer masonry leaves together. Provide temporary propping where the manufacturer or structural design requires it.
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Complete the cavity and weather details
Install the specified DPC, cavity tray, stop ends, weep vents, insulation and cavity closures. Requirements vary according to the lintel profile, exposure and wall design.
UK Building Regulations
In England, the structural stability of walls, lintels and beams is covered by the Building Regulations and associated Approved Document A guidance. Wales, Scotland and Northern Ireland operate their own building-regulation or building-standards systems.
Building Control may require confirmation that the proposed lintel has adequate capacity, bearing and support. This is particularly relevant when:
- a new opening is being formed in a loadbearing wall;
- an existing doorway is being widened;
- a failed lintel is being replaced;
- the loads or construction are unusual;
- a proprietary load table does not clearly cover the application; or
- a structural steel beam is proposed instead of a standard lintel.
For more detail, see our guide to Building Control approval for lintel work.
Fire door openings
Where a doorway forms part of fire-resisting construction, the lintel is only one part of the complete wall and doorset detail. The opening, frame, fire stopping, seals, surrounding construction and installation tolerances must follow the project specification and applicable fire-safety requirements.
Do not assume that a standard internal-door detail is suitable for a fire door simply because the lintel itself is concrete or non-combustible.
Lintels for Double Doors, Patio Doors and Bifold Doors
Double doors, sliding patio doors and bifold doors create wider structural openings than a standard single doorway. As the span increases, the lintel may need to carry more masonry and may also be affected by floor, roof or point loads.
Do not select a long lintel purely because it physically reaches across the opening. Its published load capacity must cover the actual span and loading arrangement.
Depending on the project, a wide opening may use:
- a heavy or extra-heavy-duty steel cavity lintel;
- a wide-inner-leaf lintel;
- a proprietary lintel designed for bifold openings;
- two coordinated lintels supporting separate parts of the wall; or
- a structural steel beam designed for the project.
There is no single opening width at which every project automatically changes from a proprietary lintel to an RSJ. Wall construction, bearing pressure, masonry height, floor direction, roof loads and concentrated loads all affect that decision.
For a more detailed explanation, read our bifold door lintel and RSJ guide, or compare Wade’s lintels for wide door openings.
Internal Door Lintels
Whether an internal doorway needs a lintel depends primarily on the wall construction.
Internal masonry walls
Brick and block internal walls generally require a lintel above a doorway, even where the wall is not carrying a floor or roof. The lintel supports the masonry directly above the opening and prevents that load from being transferred through the door frame.
Concrete lintels are frequently used in internal blockwork because they are economical, compatible with masonry and suitable for plastered finishes. A fair-faced concrete lintel may also suit utility, commercial or communal areas where the structure remains visible.
Steel box and single-leaf lintels may be used where the wall width, span, load or construction programme makes them more appropriate.
Loadbearing internal walls
A loadbearing internal wall may support floors, roof members or other parts of the structure. The lintel must therefore be selected for those imposed loads as well as the masonry directly above the doorway.
If the direction or magnitude of the load is uncertain, the lintel should be specified by the project designer, structural engineer or manufacturer’s technical team.
Timber and metal stud partitions
A non-loadbearing stud partition usually uses a timber or metal header between the studs. This forms and braces the door opening but does not perform the same function as a structural lintel supporting masonry.
A header in a lightweight partition must not be treated as a substitute for a lintel where masonry or another structural load is present above it.
How Much Does a Door Lintel Cost?
Door lintel prices vary too widely for the door width alone to provide a useful estimate. The main cost factors include:
- steel or concrete construction;
- overall lintel length;
- section size and profile;
- cavity width and inner-leaf width;
- standard, medium, heavy or extra-heavy duty;
- thermal performance;
- manufacturer and product range;
- standard or made-to-order manufacture;
- delivery distance and handling requirements; and
- whether one lintel or separate supports are required.
A standard concrete lintel over a small internal opening will usually cost less than a long, thermally broken or extra-heavy-duty steel cavity lintel. However, the purchase price should be considered alongside the complete wall detail.
For example, one steel cavity lintel may support both masonry leaves, whereas a concrete solution may require separate inner and outer supports, additional damp-proofing details and more handling on site.
Recommended starting point
Identify the wall, opening and load before comparing products
Measure the clear structural opening, establish the wall construction and cavity width, and check what the lintel must support. These details will narrow the range far more reliably than the finished door size alone.
If the load or wall construction is unclear, contact Wade’s lintel team with the opening size, wall details and project specification before ordering.
Door Lintel FAQs
How much wider should a lintel be than the door opening?
The lintel must extend beyond the clear structural opening far enough to provide the specified bearing at both ends. Many steel lintels require 150mm at each end, making the lintel at least 300mm longer than the opening. Some concrete ranges publish different requirements for smaller openings, so check the exact product data.
Do all internal doors need lintels?
No. A doorway in an internal masonry wall will normally need a lintel. A doorway in a non-loadbearing timber or metal stud partition will usually have a header instead.
Can a concrete lintel be cut to length?
Some precast concrete lintel ranges are approved by their manufacturer for cutting on site. Others may not be. Confirm this against the exact product data before cutting, and follow the manufacturer’s requirements for protecting any exposed reinforcement.
Can a steel lintel be cut?
A proprietary steel lintel should not be cut or modified unless the manufacturer has expressly approved the change. Cutting may alter the section, remove corrosion protection and invalidate the stated load performance.
Can timber be used as a door lintel?
Timber headers are routinely used within timber-framed and stud construction. Timber should not be substituted for a specified masonry lintel unless the complete structural arrangement has been designed for that purpose.
How do I know if an existing door lintel is failing?
Possible warning signs include diagonal cracking above the doorway, displaced masonry, rust staining, visible sagging or a door frame becoming distorted. These symptoms do not prove lintel failure by themselves, but they justify further investigation.
See our guide to lintel failure, repair and replacement for a more detailed assessment.
