The message
from Bramble Bramble@none contains these words:

I have a leaking yorkshire stone roof. It is patched up in several
places and there doesnt appear to be any lead flashing between my
house and the next on the hill. I would like to have the roof stones
turned and replaced where broken. I would like to keep stones rather
than go for man-made tiles. Should a roof newly covered in yorkshire
stone be just as water tight as perfectly fitting man-made tiles? If
not I may change my mind and get tiles instead 8)

AIUI it is normal practice to felt a roof when the stone slates are
turned. I would be surprised if a tiled roof was completely watertight
in all circumstances without felt of some sort below. Stone slates,
particularly the rougher sort with a great variation of thickness would
be much more prone to wind blown water ingress.

Be aware that you may need planning permission to change to a tiled
roof. I doubt whether building regs would be an issue as, unlike slate
slates, Yorkshire stone slates are heavier than clay or concrete tiles.

I am going to get several quotes. I would like to have a simple
contract as it sounds like it is going to be expensive. Has anyone
had experience of hiring people under the masterbond scheme? Did you
find it worthwhile - where the builders any more reliable/professional
than those outsie the scheme?

Be prepared for a considerable expense. ISTR the going rate was about
£3000 25 years ago. 2nd hand slates have no doubt got considerably more
expensive over the years and scaffolding would now be compulsory under H
& S legislation. No idea whether the Federation would be a good idea but
there should be a number of roofers in your area specialising in stone
slate roofs.

If I understood correctly it cost Strawbridge (Its not easy being green)
£50,000 to have his large farmhouse roof replaced with cheap imported
slate slates and would have cost twice as much using a home hewn variety
but he made no attempt to salvage any of the existing slates.

--
Roger Chapman