Slate is chemically inert, non-porous, does not warp, shrink or rot, it is particularly suitable for copings and cappings; the need for damp proofing is eliminated. Slate copings are effective where a precise skyline to a building is desired.
Three types of slate copings are available: flat, weathered and saddleback. Each type is available in sizes to suit various wall thicknesses and should overhang the brick or concrete wall face on one or both sides.
- Flat Coping: This is sometimes laid to falls for water run-off and normally polished on the face and edges. Copings and cappings, which overhang, are grooved on the underside for throating.
- Weathered Coping: A solid section, worked in itself, fine rubbed on the face and edges and grooved for throating. In addition it is weathered in one direction for the entire width. The fall is normally 12mm but this dimension may be varied. The minimum is 6mm on 25mm thick section.
- Saddleback Coping: As before, a solid worked section rubbed on the face and edges and grooved for throating. In addition it is weathered in two directions from the centre to the edges. As for weathered copings, the fall is normally 12mm but this dimension may be varied.
For returned ends, both throating and weathering are returned. The details on the face of the sheet illustrate the various standard junctions in use. These may be adapted to meet special needs. Normally the copings are made in straight lengths but, subject to certain limiting conditions, may be manufactured circular on plan. The illustrations overleaf show standard butt joints, which have proved, popular and satisfactory over the years, when care is taken to ensure adequate pointing with an approved modern high performance mastic such as polysulphide. The minimum joint size is normally 6mm.
As shown on the face of the sheet, copings are supplied in sizes from 600mm up to 1.5 metres in length and, unless otherwise requested, will be manufactured in random sizes within these dimensions.
Slate copings should be stored in an area and in a manner that will keep them in prime condition. They should be handled with respect and must be carried to the fixing point. “Walking” the copings on its ends will result in damage and impair the final appearance.
Slate copings should be fixed on 12mm solid mortar bed. The joints between slate pieces should be a minimum of 6mm (joint design should be in accordance with advice and recommendations of chosen mastic supplier) and pointed with a black (non-hardening) mastic. Pieces should be doweled together by means of circular dowels at each joint. At approximately every 1.5 meters a 4mm non-ferrous hook cramp should be used (see face of sheet) to anchor the coping. The copings may be supplied drilled for cramps and dowels and the latter also supplied if required. Architects should indicate expansion joints where necessary to allow for any possible structural movement. These may be taken up by the use of larger calculated joints (see face of sheet). Expansion or movement joints should also correspond with similar structural joints.
The slate used for the manufacture of copings and cappings is especially selected for the uniformity of its natural blue-grey colouring. Exposed surfaces are rubbed smooth.
Wincilate Copings can be seen at:
- The Museum of London, Barbican
- Presto Supermarket, Woolwich,
- Commercial Union Offices at Whyteleafe, Surrey,
- Hinkley Health Centre,
- West Hampstead Power Signal Complex for British Rail,
- Sports Centre, Kirkstall Lane, Leeds,
- Cliffs Pavilion, Southend,
- Needham Research Institute, Cambridge,
- Sandwich Sports Centre, Sandwich,
- 3M, Harlow, Essex