Timber decay and woodworm
An air brick was found only because a kitchen plinth was off, and the other vents on that wall are hidden by units. What floor void has not been shown to be ventilated?
The floor void behind that kitchen wall has not been shown to be ventilated. One air brick was found only because a plinth was off, and the other vents on that wall are hidden by units, so the survey has a single accidental view rather than a clear run of vents. A brick found behind a plinth may itself be blocked, and the hidden ones may be open, closed or absent. The inspection has not shown air moving through the void, has not seen the void, and has not decided the joists are dry. One uncovered brick is not a ventilated floor.
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?
Suspended timber floors rely on air bricks to move air through the void and keep the joists from sitting in still, damp air. Kitchen units are a common way those bricks get covered. Finding one because a plinth was off tells you the fitter left at least one brick in the wall. It does not tell you the grille is clear, that the sleeve crosses the cavity, or that the next bay of floor is open to it. Vents still hidden by units were not inspected.
Ask for the remaining plinths on that wall to be lifted so the other openings can be seen, and do not tell a lender the floor void is ventilated. If the void itself must be understood, that is a look under the floor, which this note does not contain. Tell the solicitor the limitation: one brick, found by chance, and the rest concealed. Concealed is not a pass.
What should you ask your surveyor?
- Which air brick did you see, and was its grille clear?
- Which other vents stayed hidden behind units?
- Did you see into the floor void at all?
What are the typical next steps?
- Treat the floor void as not shown to be ventilated.
- Do not count one uncovered air brick as a clear void.
- Ask for the hidden vents on that wall to be uncovered.
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 found brick is open, is the whole void ventilated?
No. One open brick, found because a plinth was off, does not show the void is ventilated. The other vents on that wall are hidden by units and were not seen. The survey has not traced air under the floor.
Can the kitchen fitter's word replace the hidden vents?
No. A fitter saying vents were left is not the survey seeing them. They stayed behind units. The floor void has not been shown to be ventilated, and a verbal assurance does not open the plinths. Hidden grilles stay hidden until the units are moved.