Roofs and flat roofs
A roof window sits on a timber kerb and the surveyor could not see a proper skirt or flashing kit. What leak path is unverified?
The unverified leak path is the junction between the roof window, the timber kerb and the covering. A skirt or a proprietary flashing kit is what normally weathers that opening. The surveyor could not see one, so the path around the kerb has not been shown to be sound and has not been shown to leak. The survey recorded a window on a timber kerb without a visible kit. It did not water-test the joint, did not lift the covering, and did not decide that the window must be replaced.
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?
Roof windows rely on a sequenced flashing, or on a properly formed upstand and skirt, so water on the slope is carried around the frame and back onto the tiles below. A timber kerb with no kit in sight may still have something hidden, or it may be a cut hole with felt turned up in hope. From the angle available, the survey could not tell. The leak path that matters is that perimeter. Until it is seen, the report cannot close it.
A roofer who fits roof windows can expose the kerb detail and say whether a kit is missing, buried or failed. Tell the solicitor the survey left this path unverified, not condemned. The home survey has not specified a new window and has not said the rafters were cut, unless that was separately seen. Staining on the reveal, if noted, is a clue to put next to the kerb, not a completed test of the flashing. Leave the covering in place on a viewing.
What should you ask your surveyor?
- What of the kerb and flashing could you actually see around the roof window?
- Did you record the skirt or kit as unseen, rather than as failed?
- Was there staining on the reveal, kept as a sign rather than a proved path?
What are the typical next steps?
- Treat the kerb junction as an unverified leak path.
- Ask a roof-window fitter to confirm whether a skirt or kit is present.
- Do not replace the window on the basis that the kit was not seen.
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
If the glass is modern, is the flashing kit assumed to be there?
No. Modern glass does not prove a skirt or a kit at the kerb. The surveyor could not see that detail, so the junction stays unverified whatever the age of the window. Asking about it again later still leaves this glass point outside what the survey decided.
Does a dry reveal mean the kerb is weathered?
A dry reveal on the day does not show the flashing. The survey still could not see a proper skirt or kit, and it has not called the junction sound because the lining looked dry. The home survey itself did not pursue this reveal question any further than the visit.