Warwick’s roofscape is one of the more visible results of the 1694 rebuild, and the council treats it that way.
The historic core is largely clay plain tile and slate on cut timbers, on buildings packed tightly together. That produces a great many valleys, abutments and junctions between one roof and its neighbour, and those junctions are where water gets in. A valley that has been patched for twenty years will keep failing at the same point until the lead is renewed properly. Sealant postpones the conversation rather than ending it.
Covering material is not a free choice here. In the conservation area it is controlled, and on a listed building the covering is part of what is listed, so like for like replacement is generally the expectation rather than an upgrade to something cheaper.
The later housing is concrete tile on trussed rafters and much simpler. The weight point still applies: a roof built for concrete tile will generally take slate, but a roof built for slate cannot always take concrete tile, and on a three hundred year old structure that margin is not theoretical.
Re-covering triggers a Building Regulations requirement to look at insulation, which in a historic roof needs designing rather than stuffing, because the wrong build up will trap moisture in the timbers. We arrange that inspection and see it through to sign off. More on our roofing page.