A lintel beam is a horizontal flexural member spanning an opening in a wall, carrying the masonry above a door, window, ventilator, or cupboard down to the supporting walls on either side. The load of the masonry above the opening is transferred to the wall by the flexural action of the lintel, so the frames of doors and windows are not unduly loaded. The beam sits with its ends built into the masonry, and its width matches the wall. A companion article on lintel beam types covers the classification and detailing of these members.
What Is a Lintel Beam and How It Carries Load
The lintel beam works in bending, like any beam, but its loading comes from the wall above the opening rather than from a floor. The masonry directly above forms a shallow arch as it settles, and the lintel picks up the load and bends. The underside goes into tension, which is why materials weak in tension need reinforcement or a stronger section. The design steps for the most common type are detailed in how to design an RCC lintel beam as per Indian standards.
Flexural action and load transfer
When the wall above an opening settles, it arches across the opening and pushes down on the lintel. The lintel bends, compressing its top edge and stretching its bottom edge. The arch action above the opening means the lintel does not carry the full triangular wedge of masonry as a simple block; part of the load bypasses it once the wall has settled. The end bearings transfer both the vertical load and the end moments into the side walls. Getting the bearing right prevents the most common lintel failure.
End bearing requirements
The ends of the lintel must sit on solid masonry for a specified length. A bearing of at least 200 millimeters is a common design minimum, and manufacturer guidance often sets 150 millimeters per end for proprietary lintels. If the bearing is short, the lintel rotates at the end, the wall crushes beneath it, and cracks run down from the opening corners.
Bearing values in practice
| Opening type | Minimum end bearing | Notes |
|---|---|---|
| Small window | 150 mm | Follows manufacturer guidance |
| Standard door | 150 to 200 mm | Common structural minimum 200 mm |
| Wide opening | 200 mm or more | Check the wall pier width first |
| Heavy masonry above | 225 mm or more | Verify with calculation |
Whatever value is used, the bearing should be checked against the width of the pier beside the opening. A lintel cannot develop its rated capacity if the wall beside it is too narrow to anchor the ends.
Lintel Beam Size Rules
Lintel sizing starts with the opening. The width of the lintel equals the thickness of the wall, and the depth follows the span. The depth typically falls between one-twelfth and one-eighth of the span, so a 2.0-meter opening needs a lintel roughly 165 to 250 millimeters deep before reinforcement. These ratios assume a uniformly loaded, simply supported member; fixings, concentrated loads, and openings within the lintel itself require a full design. The distinction between a beam and a lintel, and how each is sized, is explained in this engineering comparison of beams and lintels.
Minimum dimensions
A minimum lintel width of 100 millimeters applies in most codes, though in practice the lintel matches the wall thickness. Depth should never drop below about 100 millimeters even for narrow openings, because the member still needs room for reinforcement cover and fire resistance.
Span and depth examples
- 1.0 m opening: 125 to 165 mm deep lintel
- 1.5 m opening: 190 to 250 mm deep
- 2.0 m opening: 250 to 330 mm deep
- 3.0 m opening: 375 to 500 mm deep, usually precast or steel
Bearing versus span
The effective span for design is measured center to center of the bearings, not face to face of the opening. Since bending moment rises with the square of the span, generous bearings increase the design moment even though they make the support safer. The calculation balances the two effects.
Lintel Construction Practices
Construction quality decides whether the lintel behaves as designed. The lintel must be placed level, its ends fully bedded, and the masonry above laid only after the member can carry it. The load cases that govern the design are worked through in types of design loads for masonry lintels with calculations.
Setting out and support
The lintel is set so its underside aligns with the finished opening height. Props or a temporary seat hold it until the mortar cures. The bearing surfaces are cleaned and dampened before bedding so the mortar bonds with both the lintel and the wall below.
Construction sequence
- Mark the opening and build the side walls up to the lintel level.
- Bed the lintel ends on full mortar joints, never on loose brick.
- Check the lintel for level and line before the mortar stiffens.
- Build the wall above in even courses, keeping the joints over the lintel full.
- Leave cast-in-place lintels to cure before loading.
- Remove props after the mortar and concrete reach adequate strength.
Support during construction
A lintel is weakest before the wall above locks it in. Props should stay in place until the mortar has gained strength, and the wall above should be built symmetrically to avoid tipping the member sideways.
The Seven Types of Lintel Beams
Lintels are classified by their material, and each type has a span range, a failure mode, and a cost profile. The full set, from timber to precast units, is described in a lintel types reference for masonry construction.
Wood (timber) lintel beams
Timber lintels are the oldest type and still common in hilly terrain where wood is available locally. Single timbers serve narrow openings, and two or three pieces can be joined for wider spans, often with mild steel plates bolted top and bottom to create a flitched beam. Timber is expensive, weak in bending, prone to decay, and vulnerable to fire, so it suits dry interiors and short spans.
Stone lintel beams
Stone lintels are cut and dressed slabs used over openings in brick or stone walls where stone is locally available. Their depth is kept near one-tenth of the span because stone is weak in tension. They crack under vibration and should be avoided in seismic areas, but dressed stone gives an architectural finish that concrete cannot match.
Brick lintel beams
Brick lintels are built from bricks laid on edge or end over the opening. They suit small spans up to about a meter. Because brick is weak in tension, the underside often carries reinforcement in the joints or a small concrete course to resist the bending.
RCC lintel beams
Reinforced concrete lintels are the workhorse of modern construction. Steel bars near the bottom take the tension, concrete takes the compression, and the section is fire-resistant and durable. RCC lintels suit spans up to about 3 meters, cover most door and window openings, and can be cast in place or precast.
Steel lintel beams
Steel lintels use rolled sections, often angles or channels, placed singly or in pairs. They are strong, shallow, and quick to install, which makes them ideal where headroom is tight or the opening is wide. For openings in cavity walls, two smaller lintels, one per leaf, often cost less than one heavy section spanning both leaves. Corrosion protection and fire protection must be specified, and the bearing is usually bedded on a pad to spread the load.
Reinforced brick lintel beams
Reinforced brick lintels combine brickwork with mild steel bars placed in the joints or in a small concrete chase at the bottom. The bars supply the tension capacity that plain brickwork lacks, extending the practical span to about 2.5 meters while keeping the appearance of brick.
Precast lintel beams
Precast lintels are cast off site, cured under controlled conditions, and delivered ready to lift. Quality is consistent and installation is fast, which suits large masonry projects. They are sized by the same rules as cast-in-place members but benefit from better curing and tolerances.
Choosing between cast-in-place and precast
Cast-in-place lintels bond with the wall above and suit irregular openings, but they need formwork and curing time. Precast units save time and give consistent strength but must be handled and bedded carefully. Small projects usually favor cast-in-place; repetitive layouts favor precast.
Lintel Beams and Wall Openings
A lintel beam does not work alone. The wall around the opening must be stable, the piers beside the opening must be wide enough for the bearing, and the whole assembly must resist the lateral forces that come from wind or seismic action. The behavior of openings in walls, lintels, and arches is treated as a single stability problem in structural analysis.
What makes an opening stable
- Piers beside the opening at least as wide as the bearing
- Lintel tied into the wall at corners
- Crack control joints at the opening jambs
- Arch action preserved above the lintel
- Opening widths kept modest where the wall above carries a heavy roof or floor
Lintel versus beam, revisited
Every lintel is a beam, but not every beam is a lintel. A floor beam carries live and dead floor loads and spans between primary supports; a lintel carries wall load above an opening and spans between short masonry supports. Sizing a lintel like a floor beam overestimates the load, and sizing it like a plain beam underestimates the stiffness needed at the supports.
Protecting Lintel Joints from Moisture
The joints around a lintel are where water finds its way into a wall. The top surface collects runoff, the ends wick moisture from the wall below, and the joint between lintel and masonry opens as materials move. Sealing these joints matters as much as the structural design, and the same logic that drives waterstop selection in construction applies to the gaps around lintel bearings: a flexible barrier that moves with the joint beats a rigid seal that cracks.
Details that keep the joint dry
- A damp-proof course under steel lintels to stop condensation and salts
- Drips at the underside to shed water clear of the frame
- Flexible sealant at the lintel-to-masonry joint, tooled smooth
- Flashings turned up the wall at the lintel ends
Long-term performance
A lintel that stays dry keeps its strength. Timber rots in damp bearings, steel corrodes where water collects, and even concrete spalls when freeze-thaw water gets into cracks. Inspecting the joints above doors and windows twice a year, and resealing when the sealant cracks, is the cheapest maintenance a masonry building gets. The same inspection catches cracked pointing above the lintel, which is often the first sign that the wall is moving.