Hospitals play a vital role in every community, and getting their design and construction right is important. At Langdon Hospital in Dawlish, a new £15m learning disability and autism (LDA) unit has been built to provide modern, therapeutic care for people with specialist needs.
To deliver the complex roof structure, Kier Construction turned to Crendon Timber Engineering, a member of the Trussed Rafter Association (TRA). Senior designer Jamie Underwood led the design.
Meeting the brief
At 49m x 59m, the scale of the new LDA building was considerable, with four pitched roofs linked by interconnecting structures. Jamie and the Crendon team were tasked with developing a design solution that combined efficiency, safety, and buildability while meeting the precise technical requirements of the client.
The roof package included posi-rafters, raised tie trusses, solid timber joists, and flat roof sections. Trussed rafters formed a critical part of the solution, delivering strength, speed of installation, and cost efficiency – benefits that housebuilders across the UK will recognise.
A further challenge was ensuring continuity of the vapour control membrane, which ran throughout the building and crossed multiple wall plate levels. Every fixing point had to be planned to avoid compromising the membrane or creating clashes with other structural components.
With ceiling joists and posi-rafters designed as independent elements rather than a prefabricated truss, additional measures were also required to provide restraint against wind uplift.
The solution
Crendon’s package covered wall plates, straps, roof trusses, posi-rafters, infill timbers, valley gutters, and flat roof materials. To simplify installation and prevent errors, Jamie produced detailed plate-level drawings that set out the various wall plate heights clearly. At the ridge level, posi-rafters were engineered with extended verticals to connect directly into the steel beams using robust nailed hangers and timber packing.
Alongside Jamie’s design expertise, estimating support came from senior designer Jeff Notton, while the site management was overseen by Crendon Contracts Manager. Installation was delivered by approved installation partners, whose close coordination with Crendon’s team ensured a smooth programme.
As a TRA member, Crendon brought not only technical skill but also the reassurance of working to the industry’s highest standards. TRA members are committed to raising quality, improving safety, and driving sustainability – principles that were central to this project.
Safety first
Health and safety are key on every project, particularly when working at height. Crendon designed the build sequence to maximise safe working platforms. Ceiling joists were OSB clad before the rafters were installed, providing a stable base for carpenters. Service voids were capped during joist installation to reduce the risk of falls, and noggins and firrings were supplied pre-cut to avoid unnecessary on-site cutting and dust.
Site safety was further supported by detailed risk assessment method statements (RAMS) prepared by Darren Kneeshaw and regular inspections to maintain a safe, clear working environment. Deliveries were carefully timed to avoid excess material being stored on-site, keeping working areas free from hazards. These measures combined to make the project safer and more efficient.
Sustainability by design
Crendon’s design philosophy is to keep things simple, and a straightforward design makes drawings easier to follow, speeds up installation, and reduces waste during manufacturing. On the Langdon Hospital project, this approach also contributed to sustainability.
By using engineered timber wherever possible, Crendon minimised the reliance on steel while reducing overall site waste. Large volumes of timber elements, such as noggins and firrings, were prepared off-site to limit cutting on-site. All timber was supplied under Crendon’s PEFC Chain of Custody certification, guaranteeing responsible sourcing.
This reflects the wider commitment of TRA members to sustainable construction. Trussed rafters are a robust and versatile solution, suitable for timber frame, masonry, and steel frame buildings.
Their speed of installation supports just-in-time delivery, reducing site storage requirements and helping projects run more efficiently.
Delivering results
For Devon Partnership Trust, the new roof structure has provided the backbone of a purpose-built facility that will make a tangible difference to people’s lives. For Kier and Crendon, it demonstrated the value of collaboration, early involvement, and technical expertise.
“This project shows what can be achieved when design, supply and installation are fully joined up,”
said Jamie.
“Working closely with Kier and our carpentry partners, we were able to overcome the technical challenges and deliver a solution that was safe, efficient, and sustainable. As a TRA member, we’re proud to set this standard of delivery on every project, large or small.”
While healthcare facilities like Langdon Hospital are specialist in nature, the lessons from this project apply directly to housebuilding, too. The same principles, simplicity in design, off-site preparation, safe installation methods, and sustainable materials, can help developers achieve faster programmes, reduce site risks, and improve environmental outcomes.
Housebuilders also benefit from the assurance of working with TRA members, who follow strict quality and safety guidance.
As Nick Boulton, chief executive of the TRA, explains:
“Trussed rafters remain the most widely used form of roof structure in UK housebuilding because they are proven to deliver strength, versatility, and cost efficiency. This project is a strong example of how TRA members apply the same trusted principles to even the most complex commercial builds, giving clients complete confidence in the outcome.”
The LDA unit demonstrates the expertise, professionalism, and commitment to sustainability that TRA members bring to every project.