Why Use Pre-Fabricated Trussed Rafters?


Trussed rafters are individually designed components made from kiln-dried, strength-graded timber joined together with steel nailplates. They provide a structural framework to support the roof fabric, ceilings and/or floors.

Trussed rafters can be used on a wide range of building types including timber frame, masonry and steel frame. Although most commonly used for domestic housing they are increasingly chosen for commercial and industrial buildings such as offices, shops, hotels and leisure centres.

Trussed rafters stand out as a sophisticated and highly-engineered product, with superior fabrication underpinned by high production standards. They are more flexible and more cost effective than many other methods of roof construction.

  • Suitable for a wide range of roof structures and building types
  • Speed of construction allows just-in-time delivery to site
  • Space saving – no on-site storage area required
  • Prefabricated components mean reduced labour costs
  • Up to 40% more energy efficient than traditional construction methods
  • More thermally efficient than alternative materials such as aluminium, steel or concrete
  • Made of timber, the only truly renewable building resource
  • Low-tech manufacturing process reduces emissions and pollution
  • Minimal environmental impact from installation


Trussed rafters play an increasingly important role in small to medium sizes commercial buildings such as hotels, schools, supermarkets etc. Architectural preference for pitched roofs, the ability to produce long spans, and the fact that they can be used on timber frame, masonry and steel framed buildings increasingly means that trussed rafters provide an ideal solution to roofing commercial buildings.

When it comes to large spans and challenging roof contours, trussed rafters enable innovative design solutions to be created, as these images illustrate. Timber sections can go beyond the standard domestic 35mm and 47mm TR26 timbers, to allow for much greater spans. Many TRA members specialise in the delivery of commercial trussed rafters, supplying roofs for hospitals, supermarkets, schools and many other large public spaces. The recent introduction of the Eurocode 5 design code to the trussed rafter design software in the UK, has further expanded the possibilities for large roof scapes, so if you have a project and you would like it assessed for viability with trussed rafters, please get in touch with us.