Project: Hathersage Swimming Pool

New 21st Century Plant Filtration and General Refurbishment & Upgrading of Hathersage Open Air Pool, Hope Valley

Tom Crooks Architecture Ltd. was commissioned by Hathersage Parish Council in 2018 to procure a new plant filtration room for Hathersage Swimming Pool to bring the existing system up to 21st Century (PEWTAG) standards.

Hathersage swimming pool opened in 1936, as a part of the King George Fifth Memorial Field, made possible as a result of a generous donation from Mr. George Herbert Lawrence, a Sheffield manufacturer of razor blades. The pool tank, surround and most importantly filtration equipment, were in desperate need of upgrading and repair. It previously took 14 hours to circulate all the water through the old filters, meaning that on busy days, the pool sometimes had to close to allow the water to be cleaned. The pool surround was breaking apart and not draining and had dulled to a murky grey and the tank lining (previously applied over the tiles) was failing.

The primary objective was to to improve water processing and reduce turnaround from 14hrs to 3.5hrs to improve water quality. This included the installation of new large-bore pipework throughout the pool enclosure from the new plant to the pool tank itself, ensuring it could continue to be heated and installation of new bored inlets and outlets through the pool wall.

Through the Architect’s recommendation, rather than an unsightly extension on the front of the building, it was agreed that the former Victorian public conveniences (latterly-bin-store) across the car-park presented the ideal discreet opportunity for conversion into a purpose-built plant filtration room. The new scheme sought to retain the existing walls (affecting repairs as necessary), rebuild the front walls to increase the capacity slightly and put a roof on (on a raised timber frame). The proposals took inspiration from the existing pool enclosure building, so that the two were of similar appearance and related to each other.

The three new filtration tanks are each 1.6m diameter and 1.8m high and require 1m above them and space around them for maintenance, so the space required to house them is not insignificant.

The proposals obtained Planning Permission from the Peak District National Park and Building Regulations Approval from the Derbyshire Building Control Partnership.

Forming the trenches for the pipework revealed the widespread failure of the concrete slab to the walkways around the pool and poor-quality substrate, in places, backfilled with debris from previous alterations/improvements, contrary to the findings of the trial pits. This, coupled with the extreme rain of November 2019 and February 2020, effectively turning the clayey soils to “soup”, resulted in a requirement for wholesale replacement of the walkways with new concrete slabs with integrated falls, expansion joints and drainage. A new slip-resistant, free-draining rubber crumb surface was applied over the top.

The pool tank was coated with a specialist aquatic fibreglass coating and new contrasting tiled edges and perimeter drainage integrated. The works sought to also improve accessibility and undertake general minor improvements throughout to safeguard the pool for the next 100 years.

The project required meticulous detailing and specification to integrate new materials and finishes with the existing, while also paying due regard for modern slip resistance ratings (concerningly many swimming pool product manufacturers seemed unfamiliar with such requirements!), ultraviolet protection and resistance to chemical corrosion as well as metric meeting imperial! Many swimming pool products on the market are not designed for outdoor use.

In the face of the Coronavirus pandemic, when faced with tiles arriving from Germany, drainage trenches from Spain and rubber crumb from Scandinavia, the works were able to continue throughout the first lockdown and complete in that summer.