Jesse Clarke
Hi Andrew, It sounds like you have a yorkshire stone slated roof. The weight of these causing old roof beams to sag is very common. You want a roofing company that specialises in this type of work. Doubtless the company that you get to do the work will want to view inside and out so as to ascertain the condition of the timbers and what restrictions there may be if it is a listed building before any recommendation could be made. This is what I specialise in and could deffinatly help you. Our details are on the internet at Max Roofings website (w. maxroofing. co. uk). we are based in the west yorkshire area and cover Leeds, Bradford, Wakefield, Huddersfield, Halifax, Burnley, Blackburn and all surrounding areas. We can also travel further if required. If you think we can help then please feel free to look us up and give me a call. Jesse.