Let the light in

Stella Rooflights replace the skylights on a historic railway pumping station conservation project.

Shore Road Pumping Station is a Grade II listed building in Birkenhead on the Wirral peninsula, Merseyside. The three-storey, Italianate-style building was designed by engineers James Brunlees and Charles Douglas Fox and constructed in conjunction with the Mersey Railway to house steam pumping engines, which drew water from the rail tunnels.

The building housed two Grasshopper Beam Engines (manufactured by Andrew Barclay of Kilmarnock), which powered pumps designed to remove water from the railway tunnel under the River Mersey. These steam-driven pumps have today been replaced by modern electric versions, however, one of the original pumps – the Giant Grasshopper – remains in the building, though it is no longer operational. The building had served as a public museum in recent years, however, today the building is closed to the public and maintained and operated by Network Rail.

The property is primarily constructed from red brick and comprises six bays of blind arcading with engaged brick columns and round-headed arches subdivided by brick buttresses to the longitudinal elevations and three bays to the gable elevations. Each elevation is supplemented by small, round-arched, single-glazed metal-framed windows, decorative brick dentils/articulation and stone hood moulds/string courses. To the south-west gable end of the main building is a single storey, duo-pitched roof outshoot of similar style.

The roof structure is of hipped construction covered with Welsh slate and clay ridge tiles, supplemented by ornamental finials at each apex. The internal roof structure is of timber queen post construction (a truss in which two posts are placed on a tie beam to support the principal rafters above, with the vertical posts held in place laterally by a collar beam). These roof trusses are in turn engaged into the external masonry walls.

Shore Road Pumping Station is located within the Hamilton Square Conservation Area – an area designated in recognition of the architectural qualities and historic significance of the realised portion of the grand Georgian development.

Network Rail is currently undertaking an extensive package of works to the Shore Road Pumping Station building to secure the building’s fabric in a historically appropriate and sensitive manner. As such, a programme of works were recently authorised for the refurbishment of the building, consisting of the replacement/repair of various elements of damaged fabric. As a major part of the refurbishment and preservation work, contractors MFG Construction appointed Stella Rooflight to design and manufacture the roof lights to replace the original skylights sited in the principal roof slopes of the building’s Welsh slate roof.

Package of works

MFG commissioned Stella to produce four bespoke roof lights of two sizes, the first two with a size of 15,260mm (w) x 1,310mm (h), and the second pair at 2,842mm (w) x 1,304mm (h). Stella divided the large roof light into five frames to ensure that framework was kept to a minimum and the amount of glazing maximised, while still providing manageable sizes. Each section consisted of five glazing bars and six glass units, giving a total of 30 panes for each roof light. The smaller roof lights were produced as single frames with a total of six glass units. Each pair of roof lights were linked together with a 316 stainless steel capping, giving the impression of two large individual roof lights sitting adjacent to each other in the roof structure.

Due to the height of the building and the inaccessibility of the roof lights, regular cleaning was not going to be straightforward, therefore, carbon or mild steel frames were not an option due to the problems that can occur with rusting if they are not regularly maintained. As all Stella roof lights are manufactured using a marine-grade 316 stainless steel frame and finished with a C5 marine powder coating, they were ideal for the project. The flush fit offered by the thin lines of steel and genuine glazing bars on each unit would perfectly replicate the original Victorian design and satisfy the planning and conservation officers involved.

As the roof lights needed to be individually designed to exactly match the size of the originals, a set of complex, detailed drawings were created by Stella, each showing the full assembly of the linked frames, as well as files for each individual component, based on the precise measurements provided.

Due to the sheer size and weight of each roof light, positioning and installation of the roof lights three storeys up in a building situated on a busy main road was one of the major challenges for the MFG team. To help overcome this challenge, Stella allowed for four lifting eyes, which were welded to each individual frame during the manufacturing process, allowing the contractor to lift the frames into position with a crane.

The entire design and manufacture process took a total of eight weeks, despite facing the unprecedented challenges that the early stages of the Covid-19 crisis posed. Having the entire supplier, manufacturing and assembly process based in the UK enabled Stella to overcome these challenges and ensure that the remaining refurbishment works were unaffected by any delay.

 For more, visit stellarooflight.co.uk