This is a question we get asked time and time again. It is very difficult to answer without full knowledge of the project, but we can help specify lintels and provide guidance on what lintel, be it steel or prestressed concrete, would help in the given situation.
Before selecting a lintel, there are six factors that need to be discovered. The video below goes through each of these, so make sure you play the video through.
The span of the lintel
This is an obvious factor to consider but we often get asked for help selecting a lintel and this is unknown. To select a lintel the general rule of thumb is to have 150mm bearing each side of the span. So if the span is 1200mm, the lintel should be 1500mm.
The wall construction
Whether the lintel is for an internal wall or outer wall, as well as the build material means an understanding of the wall construction is required before you can select the appropriate lintel. Some lintels are specifically made for certain constructions e.g. Timber Frame Lintels.
The height and type of masonry above the lintel
This is imperative to know as it affects not only the load-bearing onto the lintel, but often the type of lintel used. If cant bricks are being used on the outer leaf of the lintel, then a short outer leaf or SOL lintel may be required.
Part of triangulation is having 600mm of brickwork either side of the span. This is taken from BS 5977-1:1981 which applies to lintels up to 4.5m in length. The standard looks specifically at the assessment of load for lintels but one key part is the 600mm threshold.
Floor joists and the span of these floor joists can have a serious impact on the load bearing onto the lintel. An appreciation of these will help lintel selection.
Finally, much like floor joists, roof trusses can impact on the load. Also, the span of the roof trusses will need to be understood before any recommendation can be made on the lintel.
These six factors are not exhaustive, but they give our technical team a keen insight into what lintel can be used for the project in mind. We have a full technical service here at Stressline including specification advice and scheduling. For more information check out our post on what to tell us when you have a question or email firstname.lastname@example.org