Quick answer: A concrete lintel beam is a horizontal beam placed over a door, window or other opening in a wall. It carries the weight of the masonry above the opening and passes it to the wall on either side. Most house lintels are RCC, as thick as the wall, with a depth of about one-tenth of the span.
The word lintel comes from an old French word meaning “threshold”. Early lintels were made of wood and later of stone. Today reinforced concrete is the most common material, because it can be cast to any size and takes both compression and tension.
What does a lintel beam do?
A wall carries load straight down. An opening interrupts that path, so the masonry above a door or window has nothing under it. The lintel bridges the gap. It takes the load of the wall above, and of any floor or roof resting on that wall, and transfers it to the masonry on both sides of the opening.
Without a lintel, or with one that is too shallow or too short, cracks appear above the corners of the opening and the frame below starts to take load it was never meant to carry. For the height at which lintels are placed in a house, see our guide to the lintel level in construction.
Types of Concrete Lintel Beams
| Type | How it is made | Where it is used |
|---|---|---|
| PCC lintel | Plain cement concrete, no steel | Small spans and light loads, non-load-bearing walls in framed structures |
| RCC lintel | Concrete reinforced with steel bars | Door and window openings in most houses |
| Cast in-situ lintel | Poured into formwork on the wall | Openings of any size; easy to adapt on site |
| Precast lintel | Made off site, lifted into place | Repeated openings of the same size; faster work |
| Prestressed lintel | High-strength concrete with tensioned steel tendons | Large spans and heavy loads |
PCC Lintel Beam
A PCC (Plain Cement Concrete) lintel has no reinforcement. It is suitable only for small spans and light loads, and is normally used over openings in non-load-bearing walls of framed structures.
- It costs less than a reinforced lintel.
- It is easy to build and needs less skilled labour.
- It lasts well if it is maintained, but it cannot take tension, so it must not be used over wide openings.
RCC Lintel Beam
An RCC (Reinforced Cement Concrete) lintel is concrete with steel bars inside it. The steel gives it high tensile strength and load-bearing capacity, which is why it is the standard choice for door and window openings in modern construction.
- It is durable and has a long service life.
- It resists seismic forces and thermal movement better than a plain lintel.
- It is cost-effective and can be designed for almost any opening.
Cast In-situ Lintel Beam
A cast in-situ lintel is made by pouring concrete into formwork fixed on the wall itself. It can be made to suit the exact opening and wall thickness.
- It allows flexibility in design.
- It bonds with the surrounding masonry, so it does not show as a separate piece.
- It is resistant to weather and fire.
Precast Lintel Beam
A precast lintel is cast off site in a controlled environment, using high-strength concrete and steel bars, and is then brought to the site and lifted onto the wall.
- The quality is consistent, because it is made under controlled conditions.
- It is durable and resists seismic forces.
- It saves time on site, since there is no formwork to fix and no waiting for the concrete to cure on the wall.
A precast lintel must rest on the wall for a minimum of 100 mm at each end so that the load is spread properly.
Prestressed Lintel Beam
In a prestressed lintel the steel tendons are tensioned so that the concrete is held in compression. This raises the load-bearing capacity and lets the lintel span large openings.
- It has very high strength and resists cracking.
- It suits heavy loads and wide openings.
- It comes in two types: pre-tensioned and post-tensioned.
What size should a lintel beam be?
The size of a lintel comes from a load calculation. The engineer adds up the lintel’s own weight, the weight of the masonry above it and any floor or roof load that reaches it, then fixes the section and the steel. Three rules of thumb describe most house lintels:
- Width: the same as the thickness of the wall.
- Depth: usually about one-tenth of the span.
- Bearing: the lintel must extend into the wall on both sides of the opening. For precast lintels the minimum bearing is 100 mm.
The span and the type of support also affect the size and the amount of reinforcement. A wide opening, or one with a slab resting on the wall above, should always be checked by a structural engineer. For other beam types in a house, see our guide to the types of beams for house construction.
How is a concrete lintel cast on site?
- Design: the loads are calculated and the size and reinforcement are fixed.
- Formwork: a temporary mould is fixed across the opening at lintel level. It supports the wet concrete until it hardens, so it must be level, rigid and well propped.
- Reinforcement: the reinforcement bars are placed in the formwork. Cover blocks and tie wires keep the steel at the required distance from the bottom and sides.
- Concreting: concrete is poured and compacted with a vibrator so that no voids are left around the steel.
- Curing: the lintel is kept wet for a minimum of 7 days so that it gains strength. See the methods of concrete curing.
- Formwork removal and finishing: the formwork is removed after 7 days, or later if curing is not complete. Masonry above the lintel continues once it can take load.
Common mistakes with lintel beams
- Too little bearing: a lintel that barely sits on the wall concentrates load at the edge of the opening, and the masonry there cracks.
- Steel in the wrong place: the main bars belong near the bottom of the lintel. Without cover blocks they sink to the formwork or float up, and the lintel loses strength.
- Removing the formwork early: the lintel sags or cracks before it has gained strength.
- Skipping curing: concrete that dries out early is weaker and develops surface cracks.
- Using a PCC lintel over a wide opening: plain concrete cannot take the tension at the bottom of the span.
- Cutting into the lintel later: chasing for conduits or fixing a rolling shutter by breaking the lintel weakens it.
Lintel beam vs structural beam
A lintel spans one opening in a wall and carries mainly the masonry above that opening. A structural beam is part of the building frame: it carries the slab and the walls on it and passes the load to the columns. A lintel rests on the wall; a frame beam is cast together with the columns.
Conclusion
Every door and window opening needs a lintel that is sized for the load above it, rests far enough into the wall on both sides and is cured properly. For most houses that means an RCC lintel, either cast in place or precast. At Walls and Dreams, lintels are built to the structural drawings and checked before the masonry above them goes up.
FAQs
What is a lintel beam?
A lintel beam is a horizontal beam placed over an opening such as a door, window or fireplace. It carries the load of the wall above the opening and transfers it to the supports on either side, which keeps the building stable.
What is the difference between a PCC lintel and an RCC lintel?
A PCC lintel is plain concrete with no steel and is suitable only for small spans and light loads on non-load-bearing walls. An RCC lintel has steel bars, so it has high tensile strength and is used over door and window openings in most buildings.
What should the depth of a lintel beam be?
The depth of a lintel is usually about one-tenth of its span, and its width matches the wall thickness. The final size and reinforcement depend on the load above the opening and should come from the structural design.
How much bearing does a lintel need?
A lintel must rest on the wall on both sides of the opening so that the load spreads into the masonry. For precast lintels the minimum bearing is 100 mm at each end.
How long should a lintel be cured?
A cast in-situ concrete lintel is cured for a minimum of 7 days. The formwork is removed after 7 days, or later if the curing is not complete.
Which is better, a precast or a cast in-situ lintel?
A precast lintel is made off site under controlled conditions, so the quality is consistent and the work is faster. A cast in-situ lintel is poured on the wall and can be made to suit any opening. Both work when designed for the load.
