The rise of timber trusses
posted: 07/Sep/2015
While the simple triangulation of roof members, the structural basis of roof trusses, dates back to very early history, the development of true roof trusses appears to have evolved during the 17th century. Instead of using buttresses to resist lateral forces from the rafters or roof beams, a tension tie was provided between the opposing roof members.
This structural principle became the basis of modern truss design now widely used for roof structures in buildings throughout the world. From simple fabricated metal plated trusses for residential buildings to massive large span architectural or industrial trusses, timber has provided cost effective, aesthetically appealing and innovative solutions for roof structures of all shapes and sizes.
The versatility of timber matched with its warmth and beauty provides the designer with immense scope to create exiting interior spaces while at the same time providing practical roofing solutions.
The evolution of the lightweight prefabricated metal plated trusses revolutionised the construction of roofs for houses but also provided lightweight long span solutions for commercial and industrial buildings.
Truss engineering has also advanced to keep pace with design trends and can match almost any interior concept or exterior roof shape.
Off site fabrication has made for better quality control of construction, and together with prefabricated wall frames, contributes to speedy construction. Modern prefabricated wall frames and trusses can be erected in less than a day.
Increasingly, modern engineered wood products are finding their way into truss construction. Glued laminated timber is often used in architectural trusses and LVL is used extensively because of the availability of long lengths and large sections. The benefits of LVL are now also to be seen in lightweight prefabricated trusses due to predictable design properties and long lengths, particularly for tension members.
Jointing is a critical factor to the success of timber trusses whether it is for structural only or structural and aesthetic purposes. In many architectural trusses the joint fasteners are featured but can also be concealed, while where trusses are enclosed in construction, the role is usually one of functionality not appearance.
Timber trusses have made a major contribution to the development of architectural concepts for more than 500 years and today still provide practical and beautiful design solutions for enclosing a space and keeping the weather out.
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