Home | Technical Times - Ed. 2 - Article 4: Lateral Restraint of Gables

Knowledge Refresh: Lateral Restraint of Gables

In this article, we’ll take a look at the common issue of gable end lateral restraint straps being installed incorrectly. A couple of things to remember when it comes to installation are:

 

  • Check that lateral restraint straps are provided at maximum 2m centres.
  • Check that the lateral restraint strap is turned over an uncut block.

 

Part A of the Building Regulations and BS8103 are that lateral restraint straps are provided at a maximum spacing of 2m, to the head of the gable wall, as shown below:

 

 

Lateral restraints gable walls  lateral restraints gable walls

 

However, it’s been noted recently that these regulations are not always followed, particularly when pre-fab roof trusses are being installed.

 

Lateral restraint straps are being placed at the node points of trusses, regardless of the spacing between the node points. If the spacing between node points is less than 2m then there is no issue, however often the spacing between node points is greater than 2m centres, particularly on larger properties. Where this is the case, additional strapping would be needed for Part A and BS8103 to be met.

 

The images below show a row of new properties being built with the roof framing in place, where the distance between the lateral restraint straps could be measured at greater than the maximum 2m centres.

 

lateral restraint gable walls 

 

 lateral restraint gable walls

 

Something to consider is that the Building Regulations and BS 8103 do not stipulate that lateral restraint straps should be provided on the node points/longitudinal bracings only, but that they can be provided anywhere along the rafter line, at maximum 2m centres. It should also be noted that the strap hook should be turned over a full block and not partial or cut blocks.

 

The practice of only installing lateral restraint straps at node points, regardless of their centres, is something we are seeing more and more of, despite it not meeting the Building Regulations and BS 8103, so it is certainly something to keep an eye on.

 

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