Bridging the centuries

Beth Davies – Building Conservation Officer

We have a new listed building in the National Park! It’s the clapper bridge carrying Ashfield Road/Wandels Lane across Danby Beck near Castleton – and it’s now Grade II listed. It was designated due to three principle reasons – its architecture, its historic interest and its rarity.

The Principles of Selection for Listing Buildings (Department for Culture, Media & Sport 2010) sets out how the Secretary of State determines whether a building or structure is of special architectural or historic interest and therefore merits listing. This states that most buildings and structures pre-dating 1840 should be listed. Historic England’s Listing Selection Guide for Transport Buildings (2011) notes that most pre-1840 bridges, where substantially intact, warrant serious consideration for listing.

Architecture – The earliest form of bridge typically surviving in use is the clapper bridge – large stone slabs spanning between boulders or abutments, built out of undressed stone. This example crossing Danby Beck is an interesting development of this most basic form in that it has carefully constructed abutments and piers using dressed stone. The herring-bone tooling indicates that the abutments date from the mid-C18 to the C19. The lack of masonry parapets and the general simplicity of the construction contributes to the interest.

Historic Interest – The absence of arches and the re-use of large slabs in their stead strongly suggest that this was a rebuilding of a medieval clapper bridge on the route between Castleton village and Howe Mill. The rebuilding was most likely in circa 1807 when the mill was extensively rebuilt and required improved access. All this contributes to the interest of the bridge.

Rarity – Clapper bridges are relatively rare nationally, especially multi-spanned examples carrying roads.

Clapper bridge carrying Ashfield Road/Wandels Lane across Danby Beck - copyright NYMNPA

The bridge has been adapted over time and still remains functional. The fact that the bridge was strengthened in 2006 by overlaying it with a reinforced concrete deck carrying the road surface does not significantly undermine its claim to special interest –the listing details note that the concrete and road surface are currently neither of special architectural nor historic interest.

The listing means the bridge is protected for the future in that any planned changes to its structure will need listed building consent which will ensure that the bridge’s special interest is conserved.

Mediaeval world goes digital

Clair Shields – Planning Officer (Building Conservation)

Our historic environment, in the form of old buildings and archaeological sites, is a precious and irreplaceable resource which provides us with enjoyment, inspiration and instruction e.g. learning how our ancestors lived and worked.

Historic buildings form an important part of the National Park’s rural and cultural landscape and provide a rich store of information about the past. Unlocking this store calls upon skills and techniques from a range of historical and archaeological disciplines to gather, analyse and interpret the evidence surviving within a building’s fabric.

With assistance from English Heritage, we are venturing into the world of 3D laser scanning to capture the workings of one of the National Parks most important historic structures – a listed water-powered corn mill with mediaeval origins which still retains a near-complete set of early 18th century wooden machinery.

Regarded as being of national importance, the mill machinery is currently at risk of being lost due to damage from severe flooding some years ago which brought about the onset of extensive wood rot. Some consolidation work is taking place, but the long-term future of the building and the machinery is as yet undetermined because of its poor state, and therefore in the mean time undertaking this comprehensive digital recording of the mill machinery is crucial in order to properly document its existence.

The screenshots below highlight the coverage and quality of the data captured by laser-scanning which can be processed and presented in a variety of ways – including line drawings of plans/sections/elevations, ortho-rectified montages of elevation images and detailed 3D models of the mill workings. The processed data will form an important record of the machinery before further conservation work takes place, since the work will involve replacing original wooden components which are rotting away and are threatening the survival of the mill machinery as a whole. Hopefully what’s left of the machinery can be physically conserved for the future, but at least now we will have the early 18th century original machinery recorded for posterity.

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