The existing roofs at Thorpe Primary School showed signs of failure, with water ingress, sunken insulation, membrane blistering, and ponding.
The Academies Trust had been advised by a third party that every roof at the site was completely saturated and required a full strip to the deck and replacement. Wanting a second opinion before committing to such a disruptive solution, the Trust instructed a client advisor to provide a feasibility assessment and investigate the condition of the roofs in greater detail.
Challenging assumptions with detailed investigations
Garland UK Technical Manager Tom Ferry conducted detailed roof condition surveys on 13 roofs across the site. These surveys were collated into a series of U-value calculations and core samples to assess the extent of water ingress. Further investigation with a Tramex moisture meter revealed minimal areas of wet build-up, largely in the gutters, that would need to be stripped back to the deck.
To independently support these findings, Garland UK recommended that the school commission a nuclear moisture map survey. This impartial assessment confirmed that less than 5% of the total roof area was wet.
The detailed results from the roof investigations ensured Garland UK could effectively advise the Trust using accurate data and develop the optimum roofing solution for Thorpe Primary School. Recognising an opportunity to rescue the roof before its condition deteriorated further, the Trust decided to reroof the entire school in a single programme of works, rather than phasing the project over more than three years.
Designing a compliant and long-term solution
The investigations identified that the existing roof build-up incorporated approximately 35mm of PUR insulation, which was insufficient to meet the school's thermal efficiency requirements and current building regulations. A warm roof design utilising the BBA-certified StressPly Flex Plus system was specified, selected for its superior tensile strength and its ability to accommodate thermal movement without the risk of membrane failure.
Approved Contractor NRA Roofing began the 3,000m² roof refurbishment by isolating the wet roof areas and stripping these back before reinstating the roof to existing levels. The roofs were then overlaid with new cut-to-falls insulation, delivering a significant thermal upgrade to the building and eliminating the historic standing water issues.
The design also incorporated tapered gutters to ensure clear drainage channels, further reducing the risk of future ponding. As the works were carried out during term time, an open channel of communication was established and maintained from the outset between Garland UK, the Trust, and all stakeholders. Distinct phases of work and regular coordination meetings ensured disruption to staff and pupils was minimised at every stage.
Delivering value, performance and assurance
The preliminary in-depth investigations and the adoption of an overlay solution, rather than a full replacement, delivered significant cost and environmental benefits. Compared with the original third-party recommendation, the approach delivered by Garland UK saved the school £98,000 in labour, materials and skip costs, while avoiding more than 30 tonnes of waste material being sent to landfill.
The thermal efficiency upgrades enabled the school to achieve a U-value of 0.18 W/m²K. Upon completion, the Trust was provided with Garland UK’s industry-leading 25 year Single-Point Guarantee for the system, accepting full liability for the design, system and installation workmanship of the project.
