Damp and moisture meters
What happens if the cooker hood discharges into the loft instead of outside?
A cooker hood that dumps into the roof void, rather than to the outside, puts steam into the loft and can wet the felt, the quilt and the ceiling edge. That is not a hole in the tiles. If the duct enters the loft, the survey can see it, but it does not test the fan.
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?
Cooking steam is a large moisture load. A hood that filters and recirculates is one design. A hood that ducts into the loft is an unfinished duct. The vapour then condenses on cold felt and timbers, and the ceiling at the edge of the loft can stain. People call that a roof leak because it appears in bad weather when the loft is cold. The tiles may be doing their job. A surveyor who could enter the loft should look for the duct end as carefully as for daylight through a gap.
Loft access is only if it is safe, and a hatch more than three metres up is a known limit on how far a survey is expected to climb. If the loft was not entered, the hood's destination may be unknown and should be written that way. Do not accept a strip-and-retile story for a duct that ends on the quilt. Take the duct to the outside air, or change the hood for a type that is meant to recirculate, and then see if the loft dries.
What should you ask your surveyor?
- Where does the cooker duct end: outside, in the loft, or not seen?
- Was the loft entered, and was the felt wet near the duct?
- Is the ceiling stain under that duct, or under a tile defect?
What are the typical next steps?
- Do not reroof the house because a cooker duct ends in the loft.
- Photograph the duct end if the loft is safe to enter.
- If the loft was not entered, find out where the hood goes before you blame the tiles.
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 recirculating hood the same fault?
No. It puts filtered air back into the kitchen. It does not wet the loft. It also does not remove all moisture, so the kitchen can still mist.
Does a tile vent on the roof prove the hood is connected to it?
No. The terminal can be from an old fan. Trace the duct, or accept that it was not traced.