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Summary

Building 18: Group of buildings including a cylinder house and chimney built in the 19th century at Powder Mills gunpowder factory

Location

Protected Status

• Scheduled Monument 1016635: Gunpowder factory at Powder Mills, a partially enclosed stone hut circle settlement and round cairn

Other References/Statuses

• Old DCC SMR Ref: SX67NW/51/18
• Old SAM Ref: 28718

Monument Type(s) and Dates

• INDUSTRIAL BUILDING (XVIII to XIX - 1800 AD to 1900 AD (Between))

Full description

Ordnance Survey, 1880-1899, First Edition Ordnance 25 inch map (Cartographic). SDV336179.

Group of three adjoining buildings shown on 19th century map with a line linking them to a circular feature, the chimney, to the north-east. Chimney object based on this source.

Ordnance Survey Archaeology Division, 1979, SX67NW99 (Ordnance Survey Archaeology Division Card). SDV350197.

Pye, A. R. + Robinson, R., 1990, An Archaeological Survey of the Gunpowder Factory at Powdermills Farm, Postbridge, Devon, 36-38, Figures 14-15,Plates 28-29. (Report - Survey). SDV254157.

Building 18: Group of adjoining buildings including a possible cylinder house, for charcoal manufacture, at Powder Mills gunpowder factory. Three phases of development were identified:
Phase 1: a two-room single-storey structure Units (c.) and (e) with doors in south and west walls, windows in west and east walls. Function unclear, though probably storage or industrial process.
Phase 2: addition of Units (a), (b), (d) and (f). The flue from Unit (a) into (f) implies a process involving heat. Main flue and chimney probably belong to this phase.
Phase 3: western portion of Unit (d) was added to the northern end of Unit (e). The northern wall of Unit (d) and the western wall of Unit (e) were thickened. Earthen mounds were were heaped against several of the walls.
The phases indicate that the function of the building probably altered over the period of production. The buildings include the following elements:
Unit (a): is of one build with Unit (b) to the north. The south and east walls survive almost to full height. Footings of the west wall survive but the northern wall has collapsed. There is a window in south wall and part of a doorway/gateway in west wall. has a doorway in centre of north wall into Unit (b). Possible blocked flue from the south-east corner into north-west corner of the possible furnace chamber Unit (f).
Unit (b): similar to Unit (a), though more ruinous. Only the north-west corner survives to anything like original height. Door through north wall into Unit (c.) and another opposite into Unit (a). Door in the centre of the west wall, and a window at south end.
Unit (c.): forms one structure with Unit (e) to the west, and its south wall is utilised by Unit (b). There are central doorways in the west and south walls and a window at north end of the west wall. The south end of the west wall has been demolished. The eest wall, and the northern part of the east wall survive to full height. Other walls are ruinous. Possible door in centre of north wall.
Unit (d): the eastern section predates the westernsection. There is a doorway into the eastern part from the east. The west wall abuts the north wall of Unit (c.). There are no other openings except a small rectangular hole low down in the wall subdividing the two sections. At a later phase Unit (d) was extended to the west, and the north wall of eastern part was thickened and embanked.
Unit (e): is the west portion of the early building which also contains Unit (c.). All the walls survive to full height. It forms a corridor down the west side of Unit (c.). There is a doorway in centre of the east wall to Unit (c.), a blocked doorway and window in west wall and a doorway through the south wall. At a later phase the west wall was thickened when Unit (d) was extended west. The window and door were blocked, and the wall embanked. The wall was later extended to the south.
Unit (f): a long, narrow rectangular structure, circa 2 metres wide, aligned east to west. Attached to east wall of Unit (b). There is a window in the south-east wall. The north-west wall is largely ruinous, though the south-west end survives and either turns to the north or has an entrance.
From the east wall of Unit (f) a covered flue runs eastwards up the hill. Its exact relationship with Unit (f) is unclear. It appears to run towards the blocked flue in the corner of Unit (a). The flue to the chimney is circa 1 metre deep and 0.4 - 0.5 centimetres wide. Its eastern portion is now open and rubble-filled, but the western portion is still capped. It enters the base of a chimney set on a plinth and about 10.5 metres high. The chimney has recently been conserved.

Pye, A., 1996, The Gunpowder Factory at Powdermills, 221-240 (Article in Serial). SDV254160.

Gerrard, S., 1998, 149192 (Un-published). SDV256665.

Cylinder house forming part of the gunpowder factory at Powder Mills.

National Monuments Record, 1999, 442786 (National Monuments Record Database). SDV248155.

Crocker, G., 1999, The Gunpowder Industry, 29, Photograph (Monograph). SDV350576.

The chimney shaft was probably associated with the preparation of raw materials.

Ordnance Survey, 2012, MasterMap (Cartographic). SDV348725.

Group of adjoining buildings shown on modern mapping.

English Heritage, 9/10/1981, Gunpowder factory at Powder Mills (Schedule Document). SDV350194.

The gunpowder factory at Powder Mills survives well and contains a complete range of buildings and other structures and features associated with the industry. Many of the buildings remain essentially intact, with only the roofs and machinery having been removed. The system of leats and trackways provides useful additional information concerning the character of the factory. The unique survival of the associated proving mortar emphasises the quality of the surviving archaeology. Together with a comprehensive historical background this represents a fine example of a gunpowder production site.
The monument, which falls into five areas, includes a gunpowder factory, a partially enclosed stone hut circle settlement and a round cairn situated adjacent to the Cherry Brook. The gunpowder factory, which is Listed Grade II, comprises at least 18 buildings involved in the production, storage and management of gunpowder. Many of these buildings contained machinery which was powered by water which was carried to the site by three large leats from the East Dart and Cherry Brook rivers. These are included in the scheduling. A system of trackways link the buildings and the river was crossed by way of clapper bridges. The gunpowder factory established in 1844 by George Frean, was certainly operational by 1846 and remained in use until 1897, when it closed as a result of increasing competition from dynamite and a slump in local mining activity. The production of gunpowder involved combining a mixture of saltpetre, sulphur and charcoal and the buildings in which the different stages of the process were carried out survive at Powder Mills. The process was inherently dangerous and to reduce the chances of cataclysmic explosions, the buildings were situated at a safe distance from each other and each had a flimsy roof which would have allowed any explosion to be carried upwards. Several explosions are known to have occurred at Powder Mills and fortunately these precautions may have ensured that no workers were ever killed. Amongst the buildings identified at Powder Mills are: grinding mills, where the ingredients were crushed separately between horizontal rotating millstones; blending mills, where the ingredients were mixed in rotating barrels; incorporation mills, where the material from the blending mills was mixed further into a single compound; a range of buildings where the gunpowder was broken, pressed, corned, dried, dusted and glazed; and finally charge magazines, where the gunpowder was stored. Further buildings on the site may have been used as storage or office accommodation. The quality of the finished gunpowder had to be tested and at Powder Mills this appears to have been carried out using two very different techniques. At SX 63777681 a proving mortar, which was used to test the strength of the gunpowder, still sits on a restored carriage. Whilst at SX 62757750 a number of large boulders have been split using a single charge, possibly the result of of testing. To the south west of the gunpowder factory stands an isolated rectangular building in which finished gunpowder was stored prior to transportation. Within the vicinity of the gunpowder works there are four quarries from which material was derived during the construction of the buildings. Parts of the valley bottom contain earthworks related to tin streamworking. Modern post and wire fences, a shed and piles of sand and other materials associated with a consolidation programme are excluded from the scheduling, although the ground beneath them is included.

Sources / Further Reading

Associated Monuments

Associated Finds: none recorded

Associated Events

• EDV6029 - An Archaeological Survey of the Gunpowder Factory at Powdermills Farm

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