It is essential that the first two layers of brickwork, or one layer of blockwork, are laid with special care and that the mortar joints both vertical and horizontal are properly filled, leaving no voids.
(1:3 cement, sand mortar is recommended).
Building blocks may be used if they are solid and have a minimum crushing streanth of 3.0 N/mm˛.
In lintels over 1.500m props must be used at the quarter points until mortarwork has matured.
Where a D.P.C. is used it must be placed over the second layer of the blockwork
Minimum bearing of 150mm each side, or as directed by the strucural engineer.
TYPE B (145x70mm)
Permissible UDL (kN/m) per layer of brickwork.
Weight: 36m/ton
Clear Span
600
900
1200
1500
1800
2100
2400
2800
3100
Without Brickwork
10.00
7.24
4.49
3.01
2.15
1.62
1.26
-
-
1 Layer of Brickwork
13.61
12.01
9.26
6.50
3.02
2.31
1.81
-
-
2 Layers of Brickwork
28.00
18.60
10.26
8.25
5.00
3.30
2.78
1.71
1.44
3 Layers of Brickwork
29.50
27.60
25.00
10.00
6.00
4.66
3.98
2.60
2.19
5 Layers of Brickwork
32.00
31.00
30.00
16.50
13.00
9.15
8.00
5.00
4.75
* Please Note: All lintels are designed in accordance with- BS 5977: Part 1: 1981, BS 5977: Part 2: 1983, BS 8110: Part 1: 1985, BS 8110: Part 2: 1985
