Durdham Down Water Tower

Concrete roof refurbishment
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Roof refurbishment of the iconic local landmark with complex 12 sided reinforced concrete form
March 2021
Authorised Contractor
Concrete Repairs Ltd / The Complete Roofing Company


Bristol Water’s Durdham Down water tower is iconic in the local landscape. Built in the 1950’s the 12 sided reinforced concrete structure was in need of renovation to ensure storage of potable water and continued local supply.

The challenge

Bristol Water’s external condition report highlighted a need for repair work and external coating to prevent further and ongoing deterioration of the water tower. Triflex were consulted on waterproofing and improvements to the roof structure.

The concrete roof structure is formed in a spoke arrangement, echoing the fin piers. Existing drainage channels were filled with asphalt and the cement forms had been painted at some time in the structure’s history. With layers peeling, it was in need of renovation and waterproofing to ensure the water tower's integrity for years to come.

With a range of telecoms equipment located on the roof, regular access is required for maintenance purposes and therefore the safety of operatives needed to be considered in the selection of finish. Additionally, improvement to the internal concrete stair to ensure the safety of workers accessing the roof was considered. The height, size and awkward access was also a consideration for materials and workforce installing the system.

The solution

The complexity of form means that liquid applied waterproofing was the ideal choice for waterproofing the roof structure. Triflex ProTect is proven to adhere to many substrates. The Triflex technical team were able to establish the performance of the Triflex ProTect directly to the coated concrete through peel and adhesion tests. In this instance, the concrete simply required a light grind and clean to ensure removal of any very uneven or dripped historic coating. The prepared surface was then ready to be overlayed with the Triflex ProTect system.

Triflex ProTect is a fully fleece reinforced system based on the most advanced PMMA resins that is both BBA and ETA certified and has the additional advantage of being completely solvent free. The cold liquid applied system provides a seamless, reliable solution that has been tried and tested under the some of the harshest conditions. The project was confidently completed in the winter months, starting in January and completing in March, as the system cures down to 0°C, allowing work to continue in the cold temperatures.

The waterproofing also had to accommodate several fiddly protrusions. The railings, lightning conductor straps and cable trays were lifted, the roof waterproofed underneath and then reinstated. Due to the system’s ultra-fast curing abilities, not only was the roof rainproof in as little as 30 minutes, but also the management of the many surface structures and services was quickly and easily accommodated.

Triflex ProDetail was also specified as a specialist system to waterproof the many detailed areas. Triflex ProDetail is a fleece reinforced system that is ideal for waterproofing upstands, gutters and roof penetrations due to its thixotropic formula, allowing it to be installed onto vertical surfaces.

The existing asphalt filled drainage was also treated with Triflex Asphalt repair mortar to improve the gutter levels that run through beam to beam walls. The gutters were then treated with the Triflex ProTect system, the same as the rest of the roof ensuring a continuous finish.

With Triflex ProTect provided in 20Kg drums, and Triflex ProDetail in 10Kg drums, materials were easy to transport up to the roof as required.

Improved safety of access

An anti-skid finish was applied to the Triflex ProTect system to demarcate designated access areas of the roof. The low slip potential (PTV>36) will improve the safety of persons accessing the roof for maintenance of telecoms structures. In addition, the existing concrete internal stair treads were overlayed with the Triflex StairCoat Eco system. The rapid setting PMMA resin based system with embedded quartz provides a long lasting and robust anti slip finish to the stair treads.

Finally, a nosing colour was applied to the internal stairs in traffic yellow further improving the visibility of the stairs in the water tower. Triflex Friction Plastic is a heavy duty textured marking and coating system, with a rapid cure and single process application. With a tough, durable finish and very high anti skid properties, not only will the stairs remain in great condition, but the safety of all those who use will be ensured for years to come.

The project was completed to a high standard by The Complete Roofing Company in conjunction with CRL (Concrete Repairs Ltd). Triflex provided technical support, advice, specifications, and regular site visits as part of the Triflex service provision.


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