Windows, doors and glazing

What should you ask if trickle vents on the windows have been painted shut?

Ask whether background ventilation is actually there. Trickle vents were put in the frame to let a controlled amount of air through. Paint, tape or a blocked slot stops that. Approved Document F is the England ventilation document for building work. A sealed vent is a moisture risk the survey can see. It is not a test of the whole ventilation system.

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?

Condensation on cold glass and mould in corners get more likely when the planned air path is shut and the house is tightly glazed. That pattern is not rising damp. The surveyor should say if they saw vents and whether those vents open. They will not measure air-change rates. That is not a home-survey test.

Opening the vents again may be enough. Sometimes the slot has been foamed up from inside. Do not cut them out until you know whether the frames can take them. There is no RICS price for restoring vents. If you are altering the windows later, the building-regulations question is for that work, not a verdict on today’s rating.

What should you ask your surveyor?

Were the vents present, painted, or missing?
Did you see mould on the glass, in the corners, or on an external wall?
Are extract fans in the kitchen and bathroom a separate comment?

What are the typical next steps?

Try the vents gently. Do not force a painted slot and crack the frame.
Read the damp and mould lines beside the window lines. They may be the same moisture.
Do not buy a positive-input fan because a vent was painted. Find out whether the vents still open.

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

Are trickle vents required in an old sash window?

Not by this page as a retrospective order. They are part of many replacement installations. An original sash is a different window. Ask before you drill one.

Does a shut vent fail the survey?

Only if the surveyor rated it. The fact they noted it means it was seen. Read the rating and the damp section together.