Improving safety at height is vital, so to help, the Trussed Rafter Association (TRA) has produced guidance on delivery, storage and installation of trussed rafters.
Delivery
Planning is essential when it comes to delivery of trusses. Information on the quantity, weights and sizes of the trusses in the roof package will be provided in advance to give site staff time to develop a safe construction phase plan for unloading, handling and installing the trusses.
A level, dry area is required for unloading and it must be clear of overhead obstructions that could get caught on the trusses.
Mechanical handling is the preferred method and it is the builder’s responsibility to ensure that suitable equipment is available for the safe unloading of trusses.
Storage
Once on-site the trusses, either bundled or individual need to be stored fully supported and restrained at all times to prevent them toppling over.
Trusses should be protected from the elements and should never be left in or near water. When longer periods of storage are anticipated the trusses should be protected with covers allowing 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 and stable removal of single trusses once the bands are removed.
Installation
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.
Here are several 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 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.
Due to the size and shape of trusses, mechanical handling is essential for all but the smallest trusses. Temporary bracing needs to be used during the initial stages of construction and where appropriate this will require input from a temporary works specialist. Once a stable base is achieved with the first group of trusses, this can be comprehensively braced providing a substantial element from which subsequent work can take place.
Nick Boulton, chief executive of TRA, said: “Educating the sector on all areas of good 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 Health & Safety Executive, we can ensure that the construction sector has access to the latest information.”
