Stone tile is the covering people worry about most, and rightly. It is heavy, hard to match and easy to damage with the wrong approach.
Q2.1What goes wrong first?
Stones rarely fail on their own. The wooden pegs or nails that hold them rot or rust, the battens soften, and water gets into the gaps between courses. A stone starts to slip, and a single slipped stone lets in enough to rot the batten beneath it. Catching that early is cheap. Waiting until a whole area has moved is not, and a stripped slope costs more than refixing a handful of stones. Moss and lichen on north-facing slopes hold moisture against the stone and the pegs, so a gentle clean-off, never a pressure jet, belongs in the maintenance routine.
Q2.2How is a slope stripped and re-laid?
When a section has to come off, each stone is lifted by hand, sorted into sizes and stacked. Sound stones go back in their courses; broken ones are made up from stone of matching geology, thickness and tone. Sandstone and limestone should never be mixed on one roof, and reclaimed stone is best taken from the roof it came from, so that other old buildings are not stripped to supply it. The Cotswold District Council technical guidance, dating from 2000, is clear that new stone is preferred to second-hand wherever possible.
Q2.3Can the timbers take the weight?
That guidance puts the weight of a stone slate roof at about 1000 kg across every ten square metres. The timbers carrying it need checking before any work begins, and a covering of a different material can change the load. Swapping stone for a lighter slate is a change of character as well as of weight, which is one more reason the matching approach comes first on any building the council values. For the manor and other listed houses, the work is planned with the owner and the council from the start. All Saints' is the working parish church, so its roof work goes through the Church of England's faculty process with the diocese rather than through the council.
Our pitched roofing page explains how we approach tiled and slated slopes in general, and the survey will say what your own roof needs.