Roofs and flat roofs
What can a survey say about slates that have been coated in bitumen or roof paint?
It can say the surface is coated and what that hides. Bitumen or roof paint covers the slate face, so cracks, thin edges and tired fixings may not show, and the survey cannot date the coating from its colour or confirm the slates underneath are sound. A coating is not nail sickness and not a remaining-life figure, and where the coat has cracked, that crack is what was visible.
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?
Coatings are sold as a way to hold a tired slate roof together. They also glue the surface so a later survey cannot see the individual slates properly. A smooth black or painted slope can hide slipped edges, open nail holes and delaminating faces. A home survey should describe the coating and refuse to invent the condition of what it covers. It should not call the roof new because the coat looks even.
Removing a coating later can damage slates. That is a reason to ask a roofer who knows coated roofs, not a reason to panic on the survey day. There is no RICS life in years for a coated slope. If the seller has an invoice, it dates the work they paid for, not the slates. Ask the surveyor which slopes are coated and which, if any, are still bare. A bare patch is often the honest sample.
What should you ask your surveyor?
- Which slopes are coated, and which are bare?
- Did you see cracks in the coating, or only a continuous skin?
- Are you able to comment on nail fixings, or are they hidden?
What are the typical next steps?
- Do not take a smooth coating as a clean bill of health.
- Ask the seller for any invoice, and read the date as the date of the coat.
- Tell a roofer the slates are coated before they quote to repair or strip them.
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
Is a coating the same as torching?
No. Torching is mortar under slates, seen from the loft. A coating is on the outside face. They can both exist. They are not one defect.
Does paint on tiles raise the same limit?
Yes, in the sense that a film hides the surface. The survey should name the covering it could actually see.