How to choose the right length of lintels to cover the opening?
Lintels are placed over door or window openings. This is an obligatory structural detail. Failure to provide the correct overlapping piece can be fatal. The lintel takes over the entire weight of the structures located above.
Jumpers are:
- metal;
- aerated concrete;
- reinforced concrete;
- wooden;
- brick (arched).
Having visited the building materials market, you can see a lot of goods for any request. But not everyone knows how to choose the length of the jumper. For houses made of foam block or monolithic buildings, the same state standard (GOST) is applicable as for brick buildings. They also need to be used to select items made in the factory. This is GOST 948 about jumpers for 2016.
As for the length of the jumpers, here you also need to take into account your own nuances.
If an opening is considered located in a load-bearing wall, that is, on which floor slabs or beams are installed, then the minimum size will be:
Opening width + 500 mm (50 cm).
That is, the ledge will be 25 cm in both directions. For clarity, the wiring diagram is shown in Fig. 1.
For example:
We have a 1.6 m wide window. Then we are looking for an overlapping element with a size of 1.6 + 0.5 = 2.1 m. The jumper installation diagram is shown in Fig. 2.
You can take more length, but less is not worth it.
What is the risk of non-observance of such a simple rule?
The most obvious thing that can be expected in this case is the formation of cracks that will diverge in the wall at an angle, as well as the loss of the bearing capacity of an entire section of the wall.
For walls that are load-bearing, that is, located inside the building, and on which other structures are not supported, the length of the lintel can be selected from the following condition:
Opening width + 240 mm (24 cm).
For example:
There is an interior doorway made in a curtain wall with dimensions of 0.7 m wide.
Then we are looking for a structural element with a size of 0.7 + 0.24 = 0.94 m.
An overlapping element with a length of 0.9 m (90 cm) does not suit us according to the condition, then we need to look for a jumper with a length of 1.0 or more.