Following a routine, regulatory inspection of a service reservoir, our CSC water industry professional (alongside the water company’s project engineer) identified a failure of the internal elastic polyurethane membrane at one of their sites, in the form of blistering, delamination and pin holing. The once-sealed access covers were also showing signs of age, with the mastic sealant being friable and lacking waterproofing properties.
The water team at CSC Services embarked upon a programme of removal and repair to replace the internal coating to both industry and clients standards.
Prior to any repairs, it was key that the existing failed coating was completely removed. This was a careful process, to ensure that further layers of coating below were not compromised. Our team utilised non-aggressive, high-pressure water jetting and hand grinding methods, an approach that allowed the successful removal of the coating but with minimal damage to substrate and intermediate layers of the existing coating system. The removal process to walls, floors and columns throughout the SR was completed over a number of weeks, due to the sensitivity of the removal and the scale of the work, at some 490m2.
The access hatches were also resealed and a new external membrane system used, to provide protection from water ingress and the elements.
An inspection of the site’s main outlet also revealed no strainer, meaning that silt, sand and other contaminants could migrate to the outlet pipe. Our experienced specialists were able to design and install a stainless steel system that prevents potential turbidity issues.
We also used polyurethane-based injection resins to fill cracks and voids with high water ingress. This solution can halt the flow of liquid in a quick fashion, forming a robust seal and stopping further damage and water ingress. The low viscosity of this material allows excellent penetration of the surface, achieving a durable elastic seal.
Now the defective coating as been removed, the project will move to the next stage, where a new Reg 31-approved coating is applied to all surface areas internally, joints over banded and the application of a new external waterproof membrane. Once complete the final result will ensure both weather and structural protection to this asset for years to come.
