Slate Menu

Setting out the Roof

For a detailed description of the process of roof slating, reference should be made to BS 5534: 2003 Code of Practice for Slating and Tiling. However, the basic steps are set out below:

1. Sort and hole slates where required. Slates should be holed from the underside to the correct gauge measured from the tail of the slate using a threaded action slate holing machine. At the same time the slates should be sorted into groups of equal thickness where required.
2. Fix the underlay as specified.
3. Mark out the roof to the correct battening gauge. The gauge may be adjusted to divide the slope length into equal margins provided the specified lap is not reduced.
4. Batten the roof (see Battening Gauges table).
5. Check the actual width of slates and mark out perpends on battens at correct centres allowing 5mm joint gaps.

Slating

6. Where required load out the slates on the roof so that the thickest slates are in the lowest courses and the thinnest near the ridge.
7. Fix undereaves courses bed up.
8. Fix the slates to perpend lines, cutting individual slates as necessary to fit hips and valleys. Each slate must be fixed with two nails.

Slate Nails

9. Slate or clout nails should be aluminium to BS 1202: Part 3, copper to BS 1202: Part 2, or silicon-bronze. In corrosive or marine atmospheres copper nails are preferable and in severe conditions silicon-bronze nails should be used.

Cutting Slate

10. In order to maintain adequate laps and allow proper fixing, slates must not be cut too narrow. In general no slates should be less than 150mm wide. At all verges and abutments, alternate courses must be started either with half-width slates or with slate-and-a half widths to maintain bond. If the half-slate would be less than 150mm, slate-and-a-half widths must be used. At valleys, hips and other places where slates must be cut on the rake, it is essential that slates are of an adequate width to accommodate secure fixings.

Nail Sizes

Minimum Batten Sizes

Nails used throughout any roof structure should comply with the standard set out in BS 1202: parts 2 and 3. Nail lengths should be calculated in accordance with BS 5534.

Slating to timber boarding (cold roof)

Unsupported underlay

Vapour permeable underlay to BS 5534