What You Need To Know When Selecting A Steel Lintel

What You Need To Know When Selecting A Steel Lintel

If you are planning on having an opening such as a window or door in a load-bearing wall you will normally need to support that load with a lintel. Due to their strength, flexibility and ease of use these are commonly made of steel. When selecting a suitable steel lintel for your build, you will need to know 3 things:

1. How is the wall constructed?

What is the Construction of the wall you require a steel lintel for? This could be one of the following:

Cavity Wall

If you have a cavity wall you will need to know the cavity wall dimensions:

  • External leaf dimension
  • Cavity dimension including insulation
  • Internal leaf dimension

Timber frame

If you require a steel lintel for a timber frame cavity wall you will need to know:

  • External leaf dimension
  • Cavity dimension

Internal Solid Walls and Partitions

Steel lintels for internal walls and partitions come in 3 varieties:

  • Corrugated lintels for non-load bearing applications
  • Channel section lintels for loadings involving blockwork and floor joists
  • Box lintels for heavier loads including point loads and wider openings

External Solid Walls

Again there are 3 varieties of steel lintels for external solid walls:

  • Single leaf lintels for a single leaf of brickwork
  • Two-piece lintels shaped to carry the two separate leaves of a 215mm fair face brick wall
  • Box lintels which have a toe for use in solid brick or block walls from 200 - 215mm thick

2. What length of steel lintel is needed?

This depends on how wide the opening is that you wish the steel lintel to span. You need to measure the size of the structural opening, the clear span between the masonry supports. Then, as the steel lintel must also rest on top of something at each end, to calculate the total length required you must add a minimum of 150mm at each end.

For example, if the structural opening was 2,100mm, you would need a steel lintel that was 2,400mm long.

3. What is the applied load supported by the steel lintel?

When selecting the correct steel lintel it is very important to know the applied load that it will be supporting. The load on a steel lintel can include:

  • Masonry
  • Loads from the roof such as roof trusses
  • Loads from the floor loads such as timber joists or concrete slabs
  • Live loads, these will depend on usage e.g. residential, commercial or industrial
  • A combination of the above

You will also need to know the load ratio. A ratio of 3:1 is where 75% of the load is on the inner leaf, which is generally the case when you have masonry and timber floor loadings. A ratio of 19:1 is where 95% of the load is on the inner leaf which is generally the case where you have masonry load and floor slabs or roof loadings.

All steel lintels are designed to support a specific safe working load if you are not skilled in calculating these loads or ratios, and you have not had them supplied by a third party who is, you should contact the steel lintel manufacturer’s technical team for advice. Alternatively contact the sales team at ABC Depot who will be happy to provide advice on what steel lintels are suitable for your job.