Damp and moisture meters

If a roof-window blind comes down wet, should every roof slope be treated as failed?

No. A wet blind on a roof window is often condensation on a cold pane or frame, soaking the fabric. It does not mean the whole roof covering has failed. A leak at that one window would still be a local junction, not a verdict on every slope.

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 are cold. A blind or a shutter left closed overnight traps a pocket of moist air against the glass, and the fabric comes down wet. That can happen with the tiles around the window perfectly seated. A leak is different: staining on the lining or the ceiling, worse after rain, often at the flashing. The survey should say which of those was present. Misted glass between the panes of the unit is a third finding, a failed seal, and it is not a roof failure either.

From the room, the outer flashing may be invisible. From the loft, the surveyor may see the lining and still not see the flashing on the tiles. A home survey does not water-test the window and does not guarantee the junction. Do not replace the covering because a blind was damp. Note whether the wet returns on cold nights with no rain, which points to condensation, or after rain, which points to the junction. Those two observations are the useful ones to write down before anyone talks about the whole roof.

What should you ask your surveyor?

Was the blind wet while the lining and the ceiling stayed dry?
Does the wetting follow cold nights, rain, or both?
Could you see the outer flashing, or only the blind?

What are the typical next steps?

Do not replace the roof covering because a roof-window blind was wet.
Separate condensation on the glass from a stain after rain.
If you need the junction checked, ask for that window, not for every slope.

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 roof window the same as a dormer?

No. A roof window sits in the slope. A dormer has its own sides and top. A wet blind belongs to the window.

Does opening the blind stop the condensation?

It lets the room air mix, which often reduces it. It does not repair a flashing leak.