Upper Keele Service Reservoir Structural Repairs & Waterproofing

Structural Repairs & Waterproofing

Upper Keele Service Reservoir, Welshpool

Client: Severn Trent Water

Main Contractor: Black & Veatch

Construction Period: 4 weeks

Structural repairs and waterproofing were required on the Upper Keele Service Reservoir, which forms the Severn Trent Water (STW) drinking water distribution network in the Welshpool area of Powys.

A structural survey of the reservoir, made of in-situ concrete, was carried to establish the extent of the repair works required. The survey established that the domed roof of the tank had been cast independently from the walls. There were signs of some movement at the interface joint between the roof and walls, as a consequence of the exposed roof experiencing considerable variations in seasonal temperature, and a technical solution was sort to overcome the risk of future cracking of the joint and water ingress.

We proposed the use of a Sika Combiflex jointing system that could be applied on the internal face of the structure and span across the roof/wall joint. The Combiflex system comprised of a Sikadur 31 structural epoxy adhesive and a Combiflex Hypalon strip, a rot proof and chemically resistant sealing sheet which provided permanent elasticity to accommodate any differential movement.

The internal surfaces of the structure had previously been treated with a waterproof coating. This had degraded and in need of re-treatment.

The internal surfaces of the tank needed re-waterproofing, and so we proposed a BASF Thoroseal FX100 waterproofing system, approved under section 31 of the Water Supply regulations for use in drinking water environments. The product was applied to the inner walls, floor and the external roof surface.