*** Covid-19 Update ***

Stonbury are immensely proud to be supporting our clients across the UK at such a crucial time and have been designated as 'key workers' by DEFRA and the UK water utility companies. Our teams are working tirelessly to help secure and maintain drinking water supplies, ensuring clean and safe drinking water is provided without interruption to critical services such as our hospitals as well as the general public. Now more than ever, the safety and wellbeing of our staff is of the utmost importance and we have adapted our safe working practices to ensure social distancing precautions are in place and that the correct hygiene practices are being followed. Safety is our priority, and we endeavour to make sure everyone at Stonbury goes home safe to their family.


Stonbury completed refurbishment works to a 40ML underground service reservoir, required due to heavy ingress from rainwater. As the reservoir comprised of two equal-sized compartments, the works were completed in two phases, spanning over a twelve-month period.

Excavation works were completed on the roof and the top screed layer was broken out to expose the roof joints, where the sealant had deteriorated. This was carried out manually due to client restrictions, which do not permit the use of any diesel-powered equipment on the roofs of clean water reservoirs.

An epoxy resin adhesive was applied using brushes, prior to the application of waterproofing bandage to 27 roof joints on the tank. However, additional flood tests were carried out and whilst the initial scope for the external works was successful, water ingress subsequently occurred through previously dry areas. These were remediated by applying the same techniques and the external repairs were completed with the installation of a liquid plastic to encapsulate the reinstated roof joints.

Internally, dehumidifiers and heaters were installed to ensure full control of the atmosphere inside the reservoir during the application of DWI Regulation 31 approved materials. Due to the dimension of the tank, sizeable generators were required to provide adequate heating and lighting during the works. However, following some complaints from residents, a permanent electricity supply into the valve house building was installed to reduce noise pollution and the requirement for the generators. This also negated the requirement for security and was retained on-site as an efficiency for future maintenance works inside the reservoir. This decision gave the utility a permanent onsite power source and saved over £50,000 in project costs.

Following the completion of surface preparation and successful pull-off tests, epoxy resin and waterproofing bandage was applied to the internal wall joints, beam ends and areas along the soffit. Detailed application and cure records were maintained at all times and data-logging equipment recorded the exact temperature within the tank. The information was downloaded and passed to the client as a record of compliance with the manufacturer’s IFU along with other QA records.

The scope of works also included the removal of the existing handrail and baffle curtain, which was made up of plastic corrugated sheeting and fixed into place with a steel frame. A new thermoplastic curtain was installed, along with a new stainless-steel handrail to ensure safe access and egress for future maintenance and testing.

On completion of the refurbishment works, an inundation test was successfully carried out and a final inspection was completed alongside the client. The team received extremely positive feedback and the client was happy for the concrete reinstatement to be completed.

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