From delivery to completion, Nick Boulton, chief executive of the Trussed Rafter Association, provides his top tips on the safe handling and installation of roof trusses.
Working at height is the single biggest risk for construction workers. According to the Health and Safety Executive (HSE), there were 38 fatal injuries to construction workers in 2017/2018, almost half of which were caused by falls from height.
As the HSE says, the risks are substantial, however long or short the work. Many have been killed who only meant to be on the roof for a few minutes ‘to have a quick look’ or to carry out a small repair.
That’s why it’s so essential to find ways to make the job safer, particularly for those working on roof construction. And it’s why, from manufacture and loading through to storage and installation, the TRA has developed safe systems of work and guidance to help builders establish good practice and reduce the number of risks involved to workers.
Here is a summary of that guidance.
Ahead of delivery, information on the quantity, weights and sizes of the trusses in the roof package will have been provided to give staff on site time to develop a safe plan for unloading, handling and installing the trusses.
The builder should ensure that a suitable level and dry area is available for unloading that is free of overhead cables that could get caught on the trusses.
Mechanical handling is always the preferred method and it is the builder’s responsibility to ensure that suitable equipment is available so the trussed rafters can be safely unloaded.
If the trusses are not to be installed immediately once delivered to site, it is important that the builder takes the time to consider how they will be stored. Trusses should be protected from the elements and should never be left in an area that is damp or in or near water. When longer periods of storage are anticipated the trusses should be protected with covers which allow for ventilation.
Care should be taken when removing bindings from a bundle of trusses. To avoid destabilisation of the bundle, prior to the removal of the bands the builder should ensure timber battens are fixed across the bundle in several locations with a part driven nail in every truss. This will allow the safe removal of single trusses once the bands are removed.
The installation of roof trusses should only be undertaken by suitably experienced and qualified personnel, such as those with a Level 2 Diploma in Site Carpentry. A full site-specific risk assessment must be carried out before any work commences.
There are a number of steps that builders should take before starting to install trusses:
- Check and read all assembly drawings and information provided by the truss supplier
- Ensure all personal protective equipment (PPE) is worn and correctly fitted
- Ensure scaffolding is in place and signed off
- Make sure that there is a safe working platform within the structure
- Ensure hop-ups and scaffolding edge protection are in place
- After reading the truss layout drawings, identify the easiest starting point using the simplest roof of trusses.
Given the size and shape of trussed rafters, mechanical handling is essential for all but the smallest fink trusses. Correct temporary bracing during the initial stages of construction is also key to the safe installation of trussed rafters and where appropriate this will require input from a temporary works specialist. Once a suitable base is achieved, usually with the first group of trusses, this can be more comprehensively braced and provides a stable element from which subsequent work can take place.
Educating the sector on all areas of best practice is part of what drives the TRA. We believe that it is important to share as much health and safety information and safe ways of working as possible. By working with a range of partners, including the Home Builders Federation and the HSE, we can ensure that the construction sector has access to the latest information.