Burton Green Primary School, located in the historic city of York, required a new roof refurbishment to replace the existing roof. It was clear that a long-term solution was required, and so by working with Project Managers Charles Garth and Principal Contractor Castle Special Projects, Polyroof worked towards providing the best solution to refurbish the ageing roof.
The work required and condition of the roof needed to be established first and so a survey was conducted on the roofing area, concluding that there were 6 flat roofs that required refurbishment.
Areas 1 to 2 were constructed of a built up felt with mineral cap sheet, 50mm PUR insulation, bituminous vapour control, asphalt, 12mm fibreboard and a 50mm wood wool slab deck with timber joists. Areas 3 to 5 were constructed of a built up felt with mineral cap sheet, 50mm Jablite insulation, bituminous vapour control, asphalt, 12mm fibreboard and a 50mm wood wool slab deck with timber joists. Roof area 6 was made up of built-up felt with mineral cap, plywood and timber joist.
The original build-up of roofs 1 to 5 needed to be stripped back to the asphalt due to the aged condition of the built-up felt and numerous leak reports were reported. Roof 6 and its original waterproofing was to be retained and made good. Later this surface would act as the substrate for the new waterproofing system.
Once the survey was completed, a bespoke specification was written and it was recommended that the roofing areas would all benefit from a high-performance waterproofing system. In addition to this, it was specified that the roof would be thermally upgraded to reduce the risk of condensation and provide lower fuel bills and energy consumption for the school, further adding benefits to making improvements to the roof.
Once the specification was complete work could officially begin. Liquid Roofing Limited, an experienced roofing contractor and Polyroof Approved Contractor, was chosen to undertake the work to this project. The proposed system for this project would be Polyroof Protec Warm Roof System.
The waterproofing system used was Protec as this system is able to offer unrivalled performance and speed of application. Protec’s liquid roof membrane has a unique flexible hybrid polymer formulation and can be applied to virtually all common roof surfaces. With this project including a warm roof upgrade by adding insulation, Protec can be applied directly to approved insulation boards as part of a simple but effective warm roof design.
The areas that were required for installation firstly needed to be stripped and removed back to the asphalt - areas 1 to 5 required this. Area 6 was then repaired of any defects and made good where necessary. All roofs required a deep clean, removing any dirt or debris that remained from the first stage. Once this preparation was completed, an Air & Vapour Control Layer (AVCL) was then installed to roof areas 1 to 5, making sure that all surfaces were smooth and without voids. Roof area 6 did not require this control layer as the original substrate would act as the vapour control layer.
Using a Polyroof Twin Pack Insulation Adhesive, the Polyroof RES insulation (T&G) boards were bonded and laid to each of the 6 roof areas completing the second stage of the warm roof upgrade. Before the last stage of the installation could begin, all joints in the insulation were sealed using taping matt and Polyroof Protec Resin. Polyroof’s extra-tough GRP trims were then installed to create neat and robust edge detailing for exposed perimeters before the main Protec system application commenced.
Once priming of all relevant details were complete, which did not include the insulation boards (due to Protec ability to be applied directly to RES insulation) the application of the main waterproofing system could begin. The first coat of Protec Resin was applied to the insulation boards/details and Polymat 450 was added to the resin to create strength in the membrane - once applied this first coat of the system was allowed to cure. Once cured, the second coat of the system was applied, this was a coat of only Protec resin. This second coat completed the system and the installation.
During the project there were some challenging aspects that required care and attention. The project featured a large array of different details ranging from installation of new substrates and trims for parapet walls to the removal of and preservation of tiles/cladding so that the Protec system could be applied correctly. These features required delicate work so that the original tiles/cladding could be reinstated after the application of the system was completed. During the project, the rooflight that was originally in place was removed and replaced but before this could happen, the Protec system was taken up the upstands and then sealed under flange.
Once the project was completed within the relevant time frame of the client and within the budget specified, the Polyroof Technical Services team conducted a detailed inspection showing a high level of workmanship which lead to the client gaining the trusted Polyroof Accredited System Guarantee. The presence of this guarantee can now allow the client the confidence in the fact that they now have a roof that will last for decades to come.
View Protec Liquid Roofing System Product Entry