Roofs and flat roofs
What did the visit record about Collyweston stone slates, about the porch roof, and about lime torching seen from the loft?
The visit recorded Collyweston stone slates on the slopes that were in view, the porch roof as a separate small covering, and lime torching only where the loft let the underside be seen. It has not decided that the stone slates are well fixed, that the porch matches the main roof, or that the torching is complete. Lime seen from a hatch is a glimpse of the underside. It is not a map of every bay, and it is not a test of the stone above.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Collyweston slates are limestone slates, usually in diminishing courses and hung in a traditional way. Torching is a lime mortar coat on the underside, once used to keep weather out. Seeing some of it from the loft shows it survives in that spot. It does not show whether it has fallen elsewhere, or whether the porch has any torching at all. The porch roof can be a different material. The survey names what was visible of each.
Ask the solicitor whether repairs have been done to the stone roof or the porch, and whether anyone has replaced torching with felt. A stone-roof specialist needs safe access the hatch does not give. The home survey has not graded the slates and has not condemned the lime. Keep the porch as its own covering when you ask questions, so a small leak there is not blamed on the main Collyweston slopes without evidence.
What should you ask your surveyor?
- Which slopes of Collyweston were actually in view?
- Is the porch roof the same material as the main covering?
- How much lime torching was visible from the loft, and where?
What are the typical next steps?
- Keep the main stone roof, the porch and the torching apart.
- Ask what repairs have been done to each.
- Use a stone-roof specialist if the slates must be judged closely.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Does lime torching mean the roof has no underfelt?
It means torching was seen from the loft in the area reached. It does not prove felt is absent everywhere, and it does not prove the lime is continuous. The porch may be built differently again. The survey recorded a glimpse. It did not strip the underside or certify the layers.
Can the porch be ignored because it is small?
The porch is a roof in its own right, with its own junctions against the wall. A small area can still let water in over a door. The visit named it separately from the Collyweston slopes. Do not drop it because the main roof is the larger covering.