What is a lintel beam?
A lintel beam is a horizontal member which rests on the door or window opening to support the portion of the structure above it. Besides, the function of a lintel is the same as a beam; it transfers the structure load to its supports.
Use of Lintels
Like the beam which transfers the loads from slab & walls, lintel beams are used to transfer the load structure supported above it.
Types of Lintel
- Wood Lintel
- Stone Lintel
- Brick Lintel
- Steel Lintel
- RCC Lintel
The wood lintel is the oldest type of lintel; currently, this is not used in construction.
In abroad, the wood pieces have been used as a lintel for home because most of the houses build up with wood material. A single piece of wood can be used as a lintel or group of wooden parts that can be used by the bolted joint.
- A bearing of 150mm to 200mm should be provided, and it should be placed on the mortar.
- The width of the lintel could be equal to the thickness of opening & depth in the range between l/12 to l/8 of the span.
- Minimum width of 80mm should be provided.
- The wood lintels are easily destroyed by fire and decay.
Stone lintels are used across the opening because of material availability. The stone lintels are widely used in construction because of its good compressive strength.
- If the stone is used as a lintel, then relieving arches should be provided since the rocks have low tensile resistance.
- A single Stone piece can be used as a lintel.
- The width of the lintel should be equal to the thickness of the opening.
- The depth of the stone lintel should be in the range of 1/10 to the length of the opening.
Technically the brick lintel will not have excellent resistance against the compressive load. So that these types of lintel could be used when the opening length does not exceed 1m.
The minimum depth of the brick lintel should be 20cm, and as usual, width is to be equal to the thickness opening.
The steel lintel contains steel angles or rolled joists. The steel lintels are used when the load is heavy, or the length of the opening is considerable. Tube separators are provided to keep the joists in position.
The steel joists are embedded in concrete to protect the steel from corrosion and fire.
Now, the RCC lintel replaced all other materials for lintel because they are fire-proof, durable, reliable, and easy to build. An excellent advantage of RCC lintel is, it can be placed either precast or cast-in-situ.
Precast lintels are used up to the span length is 2m; if the opening length exceeds 2m, then the lintel would be constructed by the cast-in-situ method.
- The M15 (1:2:4) concrete grade is usually used for lintel concrete.
- RCC lintels can increase the construction activity because sunshade can easily project from RCC lintels.
- The depth and reinforcement depend upon the span of opening.
Standard Lintel Size for Door Opening & Reinforcement Details
Example Calculation of Lintel beam Size
Assume that you need to construct a lintel beam for a door opening of 1 metre length
Opening length – 1m, Bearing 200mm at both ends
So length of lintel beam L = 1+0.2+0.2 = 1.4 m
Depth = 1.4/(20+1) = 66mm
L = Effective Span (Incl Bearing) l = Length of opening b = breadth of wall
Minimum Bearing = 200mm at both ends.
Depth of lintel = L/(20+modification Factor)
Modification Factor as per IS 456
Happy Learning 🙂