文档介绍：32 Methods of repairing and consolidating stone buildings
mastic based on linseed oil and sand with rot-resistant and retain their tight hold on the slate,
litharge. are often substituted.
9. The gutters should be re-fixed with the roofing Individual slates which have slipped may be
felt carried over into them. secured with slating hooks. New slates may be fixed
10. The contractor should, wherever possible, leave in the same manner without cutting nails. Although
on the site an assortment of sound slates to hooks may be visible they allow minimum interfer-
enable localized repairs to be carried out when ence with the roof and avoid some of the risks to
necessary. good slates when cutting nails with a ripper.
Large-scale failure of fixing almost inevitably
means the stripping and relaying of the roof using as
many new slates as necessary. It is important that the
Repair of slate roofs coursing pattern is maintained and that any
polychromatic designs or special shaped slates are
True slates provide a much lighter roof covering than retained.
tilestones. They form a good waterproof roof when Another method of securing stone slate on slate
properly laid, close butted and accurately lapped roofs which has been used in a limited way over the
vertically and horizontally. The failure of slate roofs past two decades is to fuc a resin-impregnated glass-
is generally as a result of the deterioration of fixings, fibre membrane to the back of the slates or,
although the slates themselves are brittle and vulner- alternatively, to attach a resin block to the back of
able to impact. They may be lifted and detached in the slate to act as a hanging nib. The first system
gale-force winds. involves the slating battens, and it is claimed that
As with any other stone there is a range of they remain sufficiently flexible to modate
durability. Slates containing significant amounts of normal roof movements. The second is less of a