Roofs and flat roofs
Tile hanging on a dormer cheek is slipping and the front window of the dormer is dry. Why can the cheek leak while the window does not?
The cheek can leak while the window stays dry because they are different faces of the dormer. Tile hanging on the cheek is slipping, and the front window of the dormer is dry. The window is a glazed opening on the front. The cheek is the side, weathered by tiles hung on battens. When those tiles slip, the lap that keeps rain out of the side is lost, even if the glass and its frame took no water on the day. A dry window does not inspect the cheek. The survey recorded slipping tiles. It has not cleared the side of the dormer.
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?
Tile hanging works by overlap and by the felt or membrane behind it. A tile that has slipped opens a path at the side cheek that never crosses the front window. Rain driven at the cheek can wet the lining, the cheek timbers, or the room below, and still leave the window dry. The inspection saw the tiles from where it could stand. It did not water-test the cheek and did not strip a tile to see the membrane. Dry glazing is a fact about the window.
Ask the surveyor how many tiles have slipped and whether the membrane was visible, and get a roofer to look at the cheek as tile hanging rather than as a window repair. Tell the solicitor the dry window is not a clean bill for the dormer side. Do not wait for a stain under the glass before you take the slipping tiles seriously. The survey separated the two faces. Only one of them showed a defect.
What should you ask your surveyor?
- Which tiles on the dormer cheek had slipped, and how far?
- Was the window dry, and did you treat that as irrelevant to the cheek?
- What of the membrane behind the tile hanging was not seen?
What are the typical next steps?
- Keep the slipping cheek tiles separate from the dry front window.
- Ask a roofer to inspect the tile hanging, not just the glazing.
- Do not treat a dry window as a sound dormer side.
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 dormer ceiling has no stain, is the cheek weathertight?
No stain means no stain was seen inside. It does not prove the cheek is weathertight, and the survey recorded slipping tile hanging. Rain may not have been driven at that side on the day. The window being dry is the same kind of limit. The defect is the slipped tiles. An unmarked ceiling has not cleared them.
Can the front window flashings stand in for the cheek?
No. Flashings at the window weather the window opening. Tile hanging weathers the cheek. The survey found the hanging slipping and the window dry. One detail does not do the other detail’s job, and the cheek was not passed because the glass had not leaked.