HOW TO RECORD A
SLATE OR STONE ROOF
10/12/15
Record products and materials [1 - 2], technical [3 - 4] and execution details and defects [5 - 7] and photograph them in context and in detail. Distinguish between inherent defects and long term deterioration [3 & 8].
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4
Record local practices, laying technique(s) and other unusual details [14 - 15].
Record the details of the roof coverings and the supporting structure, both before it is disturbed [8] and during stripping, including the materials or products, their dimensions, shape, composition, colour, texture and the way they have been assembled.
3 Deterioration.
4 Execution defect. No side lap.
1 Material. Pennant stone slate.
2 Damage to leadwork - theft.
5 Execution defect. Solid bedding has drawn water to the battens.
6 Execution defect. Pig courses.
7 Execution defect and consequence. Pig course with no head lap results in wet battens (arrowed).
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8
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10
8 Long term deterioration. Mass slippage caused by grouting and slurrying.
9 & 10 If photos with scales are taken perpendicular to the slating, dimensions such as laps can be checked after the survey.
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12
11 & 12 Slipped slates digitally repositioned on their correct laths to demonstrate the original triple laps.
Courses should be numbered for photographs [10] so that the original arrangement can be demonstrated using image editing software [11 - 12]
Use checklists to record materials, products and constructional details as far as is possible and appropriate [13].
A courses by course schedule of margins, headlaps, side lap ranges, slate lengths, maximum and minimum widths, and lath or batten gauges should be produced as stripping takes place.
The type and size of the various materials should be recorded as well as their condition and, if they have deteriorated, whether they need to be replaced or can be reused.
13
Plants and animals. Provide a photographic record of all vegetation (mosses & lichens) growing on slates. A bat survey will normally be carried out prior to work but any evidence of bats not identified during the survey should be reported immediately and work stopped [16 & 17].
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14
14 West Country slate ridge.
15 Mounter eave and rag verge with scantle slating.
19 Water damage at failed valley and from damp masonry.
18 Lath failure due to rusted nails.
Record and photograph any water penetration, timber rotting or insect damage and relate to any original roof defects or deterioration since construction [18 & 19].
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17 Moss on limestone slates.
18 Lichens on slates.
21 Remains of plaster infill to roof truss.
20 Smoke blackened ridge and ceiling above later slating repair.
Record and photograph any constructional details or artifacts uncovered during the works [20 & 21].
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21
When photographing slating always include views straight on to the surface, and include a horizontal and vertical scale with 25mm bars to provide a record of the slate lengths, head and side laps and the lath gauges [9 - 10].
Slating should be photographed with three or four courses as appropriate raked back so that the lapping is shown [9].
‘The roof coverings are to be reinstated in their existing form except where inappropriate and unsympathetic changes have occurred, or where technical defects in the existing details are identified during recording and stripping.’