Amendments to the British Standard (BS) for trussed rafter roof design, BS 5268-3, have allowed non-domestic roof spans to extend up to 17m and have “reduced the amount of engineering time needed to design large span roof structures”, according to the TRA.
“The guidance and rules given make it easier to produce bracing solutions whereas before, certainly in the case of longer spans, these to some extent relied on the skill of the engineer,” said Chris Shelton from Dover Trussed Roof Co, a TRA member.
“This in turn gives confidence in the solutions offered because they are meeting the requirements of the BS.”
The association has noted that this has benefitted nursing homes, private hospitals and small retail outlets as the extra costs previously attached to installing trussed rafters have been negated.
However, the TRA added that the industry faces a challenge to react to the more complex designs that are found in apartments and commercial developments.
“The switch from low rise housing to apartments has reduced numerically the demand for roof trusses in the housing sector,” said the association. The challenge for the roof truss industry has been to react to the greater level of design needed to satisfy the much more complex apartment and commercial market.”
The use of trussed rafters has been growing in the non-domestic market for the last 10 years according to the TRA, with one third of those manufactured used in developments such as supermarkets, hospital extensions and school buildings.
