What is Lintel?
A lintel is a horizontal member, which are usually placed over the opening portion of a building like doors and windows. Lintel behaves just like a beam. It carries the load of the masonry work over the opening part, and transfers all the load to the supporting walls. The lintels should have at least 20 cm bearing on masonry on either side.
Different Types of Lintel
In this article, we will discuss about the different types of lintel used in building construction. lintel can only be classified according to the materials used in their construction. They are –
- Timber Lintel
- Stone Lintel
- Brick Lintel
- Reinforced Brick Lintel
- Steel Lintel
- R.C.C Lintel
- Thin Lintel
Note: Thin lintel is an another type of lintel which is classified according to their thickness.
1. Timber lintel
Timber lintels were very common in use in the olden days when technology was not very advanced. Also at present time, some wooden lintels are used in building. But now it has become difficult and expensive due to the lack of timber availability.
It is also easily affected by white ants and other insects and that is why it is not preferred for modern construction. They are combustible and therefore not suggested for use in fireproof construction. The minimum depth of wooden lintels should be 7.5 cm. Timber lintels may be in a single piece or of built-up type.
Timber lintels should be made of sound and hard wood. The best and recommended wood for timber lintel is teak, sal, rosewood etc.
They are flammable and therefore not suggested for use in fireproof constructions.
The depth of the timber lintels should not be less than 7.5 cm, and width should be equal to the thickness of the opening.
Timber lintel can be of a single piece or of built-up type.
Without the proper seasoning, the timber is liable to decay as well as destroyed by fire.
If the timber lintel used for large spans, it should be designed using flexural formula.
2. Stone Lintel
Lintel made of stone is called as a stone lintel. Stone lintels are very common in areas where the stone is widely available. They can be used as single pieces or in groups of several pieces. Stone lintels have good compressive strength but poor in tensile strength and therefore they are not suitable for a long span. If it used over a span of 1 m, then most of the load should be relieved by providing a relieving arch.
The thickness or depth of the stone lintel may be considered on the basis of the thumb rule that the thickness of the lintel should be 1 mm for every 10 mm span. We all know that the stone is not easy to handle and also required dressing work before it used, and hence prove costly.
3. Brick Lintel
The brick lintel is an another types of lintel which are mainly used for a short span, not more than 90 cm. Usually, first-class bricks are used to build brick lintels, which are either laid on end or on edge.
In the construction of brick lintel, first of all, a temporary supporting timber structure is constructed. The thickness of the lintel should be multiple of brick courses.
As I said before, for long spans and in case of heavy loads, this lintel should not be used. However, if this lintel is to be used for a large span, then reinforced brick lintel may be used.
Read Also: Characteristics of First Class Brick
4. Reinforced Brick Lintel
Is brick lintel possible for long spans? Yes, possible if they are reinforced by a steel bar. When steel bars are provided with brick lintel is known as Reinforced Brick Lintel.
In this case, the bricks are arranged in such a way that 20 to 40 mm gap are left, lengthwise, in the brick row. After that, Steel bars are inserted into this gap. And finally, empty places are filled with rich cement mortar or cement concrete.
In case of 20 mm gap, cement mortar is used to fill them. But, in the case of a 40 mm gap, concrete is used to fill this gap. The depth of the reinforced brick lintel should be minimum of 100 mm.
5. Steel lintel
Steel lintel is another type of lintel, consisting of angle irons or rolled steel joists. In case of large span and heavy loads rolled steel joists are used. Whereas, for small span and light loads angle irons or steel channel section are used.
Sometimes, steel joists are embedded in concrete to make it fir-proof, it is mostly used in case of the shop front, bay window etc. Angle or channel section are generally preferred for small opening such as normal windows, bathroom windows etc.
6. R.C.C lintel
R.C.C lintel or reinforced cement concrete lintel is one of the most usable lintels at present time. This is the lintel that has partially replaced all other types of lintels.
This lintel has fire-resistant properties as well as corrosion-resistant properties. It is durable, strong and easy to construct. This type of lintel is more economical than any other types of the lintel.
It can be used for any span and also for taking any loads. These lintels may be precast or cast in situ. In the case of a small span say about 1.5 m to 2 m precast lintels are used. In case of large span, cast-in-situ lintels are used. Generally, M15(1:2:4) grade of concrete mix is used for casting of an R.C.C lintel.
The amount of reinforcement and depth required for an R.C.C lintel depends on the span of the lintel, and the total load to be supported by the lintel.
7. Thin Lintel
The thin lintel is nothing but R.C.C lintel having a thickness around 75 to 100 mm. Above this R.C.C lintel, a brick or stone masonry is created and which acts as a part of this lintel.