A lintel is a horizontal member which is rest 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.
Types of Lintel
- Wood Lintel
- Stone Lintel
- Brick Lintel
- Steel Lintel
- RCC Lintel
The wood lintel is the oldest type of lintel, at present, this is not used in construction. In abroad, the wood pieces have used as a lintel for home because most of the home totally builds up with wood material.
A single piece of wood can be used as a lintel or some other number of wooden pieces can be used by the bolt joint.
- A bearing of 150mm to 200mm should be provided and it should be placed on the mortar.
- The width of the lintel is could be equal to the thickness of opening & depth in the range between l/12 to l/8 of the span.
- Minimum width 80mm should be provided.
- The wood lintels are easily destroyed by fire and decay.
Stone lintels are placed across the opening where the material is available more. Still now, 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 stones 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 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 is not having good resistance against the compressive load. So that these types lintel is 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 large. 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 of its are fire-proof, durable, strong and easy to build. A good 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
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
Opening length – 1m
Bearing 200mm at both ends.
L = 1+0.2+0.2 = 1.4
Depth = 1.4/(20+1) = 66mm
You may follow the Reinforcement detail as shown above diagram.
You may interest to read how to calculate the material quantity for concrete.