How to make historic structures safer – and stand the test of time


Our macro synthetic fibres were used to replace the spillway at the Grade II-listed Butterley Reservoir in Marsden, West Yorkshire.

Renovate, not ruin

The Butterley Reservoir spillway controls the flow of water from Butterley, so it doesn’t erode or flood the embankment. Designed in 1906, the historic structure was due for major safety repairs to comply with the Reservoirs Act 1975. But the local community was concerned replacing historic stone with concrete would spoil the reservoir’s natural beauty.

With this in mind, Yorkshire Water hired contractor J N Bentley to raise the spillway walls, and replace the steep steps with a flat slope to contain floodwaters. It also planned to replace some of the collapsed stone masonry with reinforced concrete. However, concrete steel mesh corrodes when it meets the alkaline reservoir water.

A natural approach

To avoid corrosion and preserve the reservoir’s natural appeal, JN Bentley used original handcrafted stones, and concrete reinforced with our Durus S400 and Fibrin XT synthetic macro fibres. These don’t rust or corrode, so the spillway structure will last longer. And because we didn’t need to cut, fix or place steel mesh, we helped save construction costs and time.


Contractor, Toureen Mangan




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Durus S400 polypropylene macro fibres

Monofilament fibre Fibrin XT

Safe spillway, happy community

Both the community and Yorkshire Water were happy with the revamped reservoir. Butterley spillway is now safer and compliant – and still an attractive feature of the natural landscape.