You will need to know five things:
- What is the wall construction?
- What is the length of the lintel?
- What is the load to be supported by the lintel?
- What is the load ratio between the inner and outer leaves of the cavity wall?
- How to interpret the load tables.
1: Select Wall Type
Cavity Wall
Timber Frame
Single Leaf
Solid Wall
Internal Partition
External Solid Wall
2: What is the length of the lintel?
How wide is the structural opening?
- Measure the size of the structural opening i.e. the clear span between the masonry supports.
- Add 150mm minimum bearing to each end.
Example lintel length = 150 + 1800 + 150 = 2100mm
3: What is the load to be supported by the lintel?
The load on a lintel comes from:
- Masonry
- Roof Loads: Truss/Attic/Cut/…
- Floor Loads: Joists/Slabs/…
- Live Loads: Residential use/Commercial use/Industrial use/…
- Combination of above
NOTE: If you are not skilled in assessing loads please contact IG’s Technical Team on 01633 486 486
4: What is the load ratio between the inner and outer leaves of cavity wall?
Total UDL kN 3:1
Up to 75% of the load is on the Inner Leaf
Total UDL kN 19:1
Up to 95% of the load is on the Inner Leaf
Load / ratio calculation:
| Inner Leaf | Outer Leaf | Total | |
|---|---|---|---|
| Load (kN) | 15 | 5 | 20 |
| Load ratio | 3 | 1 | < 3:1 |
5: How to interpret the load tables
L1/S 100
This is the specification code that you should reference when contacting an IG Engineer.
L1 Lintel type 1
S Standard Loading
100 100mm Cavity Width
For cavity widths 90 -105mm
The lintels listed in this table are designed for cavities 95mm to 105mm wide.
Manufactured length 150mm increments
Denotes the lintel lengths including end bearing. The 2100mm long lintel in Example 2 is listed in this column.
Total UDL
The UDL (Uniformly Distributed Load) is the total load in (kN) that is uniformly distributed along the span of the lintel relative to the load ratio.