History

A fanhouse was built in 1886 by Thomas Walker to house an 18'(5.5m) diameter fan by Messrs Walker Bros of Wigan which ventilated the Severn Tunnel by drawing air up the shaft and thus in at both ends of the tunnel. How much of this fanhouse still survives is uncertain, because the fan was replaced in 1924 by a much larger one with a diameter of 27' (8.2m) and a width of 9'(2.7m). This was supplied by Walkers again, as was the horizontal tandem compound steam engine which drove it. This fan blew air down the shaft, which proved a more effective way of venting the bottom of the tunnel under the river, which was some distance from the bottom of the shaft. The house was either rebuilt at that date or was heavily modified. The engine house is not tall enough for large beam engines, which it perhaps did not need, but it is too tall for a horizontal engine.

Exterior

This building is constructed of red brick, with roofs of Welsh slate as far as can be seen. Its main elevation (south) has what looks like the base of a water tank to the left. This has blocked arched openings on two floors and two small square ones above, cornice and flat roof. The fan housing, with its distinctive vertical circular shape, is in the centre. To the right is the gabled engine house with two tiers of elliptically headed iron framed windows and a circular light in the low pitched gable. The rear elevation of this section is a repeat of the front. The side elevation, facing the river Severn, has two floors of six windows as before.

Interior

The interior was not seen at resurvey. It was built to house an engine to drive the fan for ventilating the Severn Tunnel.

Reasons for Listing

Included as a rare survivor of a fanhouse of the type which was used to ventilate Victorian mines and tunnels but which are now largely redundant, but here remains necessary for Britain's second longest railway tunnel, even though it is no longer used by steam locomotives.

External Links

• Cadwr Listing
• Wikidata Q29501109

External links are from the relevant listing authority and, where applicable, Wikidata. Wikidata IDs may be related buildings as well as this specific building. If you want to add or update a link, you will need to do so by editing the Wikidata entry.

Recommended Books

• 
  Listed Buildings and Other Heritage Assets
• 
  Old House Handbook 2 Books Bundle Collection (Old House Handbook: A Practical Guide to Care and Repair,Old House Eco Handbook: A Practical Guide to Retrofitting for Energy-Efficiency & Sustainability)
• 
  Kent: North East and East (Pevsner Architectural Guides: Buildings of England)
• 
  Bristol (Pevsner Architectural Guides: City Guides)
• 
  London 1: The City of London: City of London v. 1 (Pevsner Architectural Guides: Buildings of England)
• 
  Harrow on the Hill: A photographic portrayal of listed buildings and structures (Historic Buildings Picture Guides)