Data processing is critical to any banking operation and this large data centre in Gloucester is a 24/7 facility providing data services for ATM cash machines operated by international banking giant, Barclays.

To ensure the smooth operation of the advanced IT equipment within the data centre, there is extensive rooftop plant and air handling equipment on the 3000m2 roof which must remain operational at all times and cannot be lifted, moved or otherwise disturbed.

The existing roof consisted of a single ply membrane installed beneath concrete slabs. The membrane had reached the end of its service life and water had penetrated to the concrete substrate, prompting the need for an urgent roof refurbishment to avoid the risk of water ingress and potential business interruption.

roof refurbishment


The roof refurbishment needed to be carried out with zero business interruption risk, calling for a system that could be installed without the use of hot works.

Strip out of the existing single ply membrane and drying of the concrete substrate were essential for the integrity of the new roofing system and this required removal of the concrete slabs, followed by reinstatement of the slabs in their original location following completion of the new membrane in each area.

The business critical nature of the rooftop plant meant that it could not be disturbed but had to be encapsulated by the new waterproofing system to avoid the risk of water ingress at the interface between the plant and the
roof surface. The circulation of air from the rooftop area within the building
via the air handling plant also meant that a low odour system was required and Sika Liquid Plastics’ cold-applied, virtually odourless Decothane Ultra liquid waterproofing system provided the ideal solution.


Sika Liquid Plastics’ Quality Assured (QA) contractor, Central Roofing, was appointed to carry out the complex roof refurbishment after a full condition survey and technical specification from the Sika Liquid Plastics Area Technical Representative.

Central Roofing prepared a 300m2 area of roof at a time, removing the concrete slabs and storing them in a holding area before stripping out the existing membrane and drying the concrete. The installation team then applied Sika Liquid Plastics’ S-Vap 5000 self-adhesive vapour control layer to each prepared roof area. 130mm Decotherm insulation board was then adhered to the substrate using Decostik and Primer 600 was applied onto the insulation, followed by another layer of S-Vap 5000. The Decothane system was then applied onto each roof area and taken up the pedestals for the rooftop plant, permanently encapsulating them within the roof surface.
Rubber pads were installed to protect the finished surface before the original concrete slabs were reinstated for each area and the installation team moved on to repeat the process with the next section on the roof.