Designing (probably) the largest trussed rafter roof in the UK
9th October 2024What would you do if you saw an opportunity to design and supply materials for the largest trussed rafter roof in the UK? The answer was clear for Acorn Timber Engineering Ltd, they tendered for the project and successfully delivered this ambitious design.
The Extra Care Scheme is a development located in the village of Welton, Lincolnshire, featuring 62 affordable apartments and 10 bungalows for individuals over 55.
TRA member, Acorn Timber Engineering Ltd, was approached by RG Carter (Lincoln) to supply metal web joists for the flat roof links between four main blocks. Sensing a larger opportunity, Simon Copley, who led the team at Acorn Timber Engineering boldly tendered for the entire roof structure, the main apartment building, and the ten bungalows.
The ambitious tender resulted in the largest single roof project the company had ever undertaken– covering almost 3,500 square meters of the roof surface and manufacturing 2,500 items including trusses, panels, and Posi Joists.
Technical successes
With nearly 3,500 square meters of roof surface and 2,500 manufactured components, the project presented a unique challenge. According to Simon and Acorn Timber Engineering, the trusses are believed to be one of the largest single-trussed rafter roofs manufactured in the UK in recent years.
The entire structure had to be designed using base-and-cap systems to comply with transport height restrictions and ensure precise alignment during installation which requires strict manufacturing tolerances.
At the same time, the trusses were designed to ensure the webs were aligned where possible to simplify the bracing pattern.
Health and safety challenges and solutions
Due to the height and weight of the trusses, safety was an important factor for the project.
Simon had arranged for the base trusses to go in first, which provided a secure platform for workers to assemble the cap trusses. It was then followed by installing the large spandrel and gable panels which were pre-cut into manageable sections for safe handling in the factory and on-site.
A permanent crane was located on-site to ensure safe unloading and construction.
Careful resource planning
The timber that was supplied adhered to PEFC standards. In the project, Simon designed structures that maximised the use of stock length, which reduced the number of offcuts. At the same time, trusses were manufactured in sizes that optimised lorry loads – reducing the number of deliveries to the site, and consequently, the project’s carbon footprint.
Lessons Learned
According to Simon, given the project’s scale, effective time and resource management was important, which was why he divided the project into smaller sections so the drawings of roof trusses could be issued in accordance with the build programme.
Batching truss design streamlined production and ensured timely processing through the factory.
Despite being proficient users of MiTek’s Pamir software, the team leveraged existing and new features throughout the project.
The Welton Extra Care Scheme is an example of seizing the opportunities when presented and being able to create numerous design solutions to achieve the overall result that will serve the community for years.
Comments from the judges of the Roofscape Design Awards
“Excellent application with detailed and appropriate information provided. Impressive scale with the technical and logistical challenges that were brought due to the size of the trussed rafters. This project needed numerous design solutions to achieve the overall design that was achieved with excellence.”
About Simon Copley
Simon has worked in the industry for over 25 years, starting at Arnold Laver in 1999; throughout his career, he has specialised in designing trussed rafters, engineered floor joists, and timber frame projects while working with various manufacturers across England.
Simon’s expertise extends to technical sales and operational roles, including his tenure with system holder Wolf Systems. Currently at Acorn Timber Engineering, Simon focuses on designing and visiting clients nationwide, bringing his extensive knowledge and experience to every project.