New roofing guide to boost housebuilders’ use of offsite components

Important new roofing guidance endorsed by the NHBC is being published this week by the Trussed Rafter Association (TRA), designed to reduce the risks, costs and waste from poor spandrel panel construction by housebuilders.

In a recent NHBC survey of 8,000 new homes sites, about 17% were already using spandrel panels. Trussed roof manufacturers report increasing interest in these offsite components, especially from large and volume housebuilders building low-rise housing and apartments.

The new guide for masonry-built homes provides evidence-based technical best practice on the design, structural requirements, fire and acoustic performance, weather protection and safe installation of spandrel panels. It is available now as a free download from the TRA website.

The guide has been developed by the TRA in association with the NHBC and the Structural Timber Association (STA) and will receive further updates following the outcome of further fire testing, currently being undertaken with the STA. The TRA and NHBC will also be providing further updates on gable detailing later this year.

Jonathan Fellingham, chairman of the TRA, said:

“As the use of pre-manufactured components and offsite construction grows in popularity, housebuilders are increasingly turning to spandrel panels.

“They provide an ideal solution to the skills shortages in housebuilding and roofing, and they help to improve safety on site, as they require less time working at height. Spandrel panels can be installed quickly, and faster installation times also mean lower costs. They also leave little or no site waste.

“But TRA members and NHBC inspectors have shared concerns about the quality of construction in some areas, so it’s vital that housebuilders understand best practice in design and installation to achieve the best results. We have collaborated with the STA and NHBC to ensure the challenges housebuilders face are covered so the standard of installation is as high as possible.”

Paul Cribbens, NHBC standards manager, said of the new guidance:

“As the housebuilding industry moves evermore towards innovative methods of construction, it is encouraging to see the supply chain embracing the challenges and ensuring that products perform as expected. This document represent a first significant step towards standardising this innovative method of construction.”

The TRA recently presented at the NHBC Building for Tomorrow roadshows, speaking to more than 700 housebuilders, addressing issues and providing guidance on spandrel panel design, manufacturing, handling and delivery, and installation.

The TRA represents over 65% of the trussed rafter and metal web joist industry in the UK and Ireland. Members include the principal manufacturers of trussed rafters, metal web joists, suppliers and professionals involved in roof and floor design and construction.