Total Contractor hears how collaborative work and the Resitrix system from CCM has played its part in providing a robust, CIF-funded solution for problem roofs at Prince Henry’s High School in Evesham.
Prince Henry’s High School in Evesham is an Ofsted ‘Outstanding’ Academy for students aged 13-18 that has worked collaboratively with chartered building consultants, PR Associates, and roofing systems specialist, Carlisle Construction Materials (CCM), to secure a Condition Improvement Fund (CIF) grant for a roof upgrade.
Despite the challenges of the pandemic, the project, which involves a 1100m2 total roof area across three roofs, is now well underway. Phase 1 and 2 are complete and phase 3 is due to take place during the summer break.
The school campus is typical of many high schools, with multiple additions to the original main building. Consequently, there are a number of different roof levels and roof areas in varying conditions, with a mix of existing coverings that had reached the end of their service life. In some areas, the roof was leaking and a small roof area over the main entrance was in need of particularly urgent attention because rain was draining onto it, resulting in ponding water.
PR Associates advocates CCM’s RESITRIX roofing system for school roof refurbishment projects. A hybrid modified bitumen and EPDM membrane, it offers torch-free installation and a certified service life of more than 50 years. The chartered building consultant worked with CCM to develop a technical specification, which contributed to Prince Henry’s High School’s CIF application.
“We often find that a collaborative approach between the school, the building surveyor and our technical team at funding bid stage is instrumental in outlining the business case for a CIF grant,” explained Paul Simms, Technical Services Manager at CCM.
“Carrying out a full condition survey and providing a technical specification at this stage ensures that the bid considers the full scope of works and that the school makes decisions that will reduce future maintenance costs and disruption.”
With the CIF funding secured, the roof refurbishment has been carried out as part of a wider programme of works, and AJR, the roofing contractor, was trained in installation of the RESITRIX system, prior to beginning work on site in January.
Andy Robinson from AJR commented: “We have a team that is very experienced in various roofing membranes but the RESITRIX training CCM provided highlighted just how easy it is to install. Thanks to the EPDM layer, the system retains its elasticity even at low temperatures, and the membrane bonds permanently to the roof on contact with the primer. It also allows us to form details with the offcuts, so there has been virtually no waste.”
The project involves a thermal upgrade to all three roof areas, along with an overlay of the RESITRIX system and improvements to drainage to address the issues with ponding water. For each roof area, the AJR team cleaned and prepared the existing roof surfaces, cutting out blisters and carrying out patch repairs where required. CCM’s technical team then carried out penetration tests to ensure there was no water tracking under the existing coverings and, once these checks had been completed, the existing roof covering was used as the air and vapour control layer (AVCL).
For the phase 1 and 2 roofs, a 130mm flat insulation board has been specified, with a tapered insulation scheme for the roof where there are issues with drainage. Following installation of the insulation, CCM’s FG 35 primer is applied directly into the insulation board and the 1 x 10m rolls of RESITRIX membrane are rolled out onto the roof. Once the membrane is in place, the AJR team peel back the release film and the membrane bonds to the primed insulation on contact, with no requirement for heat activation or mechanical fixings.
Each roll of RESITRIX is installed with a 50mm lap, which is sealed using a hot air welding tool. The roofs involve a range of details, including rooflights – which are being replaced – drainage outlets, a parapet wall and a tank room, and the AJR team can use offcuts of the membrane to form these details because the material bonds to itself.
Richard Pill, chartered building consultant and PR Associates added: “We recommend RESITRIX for school projects because it not only offers excellent performance for an extended service life but it enables installation in an occupied school building with no hot works or unpleasant odours.”