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Flood risk

What should you ask about air bricks if a flood map has already worried you?

Ask what the air bricks are doing, and do not confuse them with the map. Air bricks ventilate a suspended timber floor or a void. Blocking them can raise moisture in the timbers. They are also a path for water if the ground outside floods. The survey can see whether they are blocked or low. It cannot tell you the long-term flood likelihood for the property, which GOV.UK says its area check does not provide either.

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?

A surveyor who finds air bricks buried by a raised path should say so, because that is a building defect they can see. Whether you later fit flood-resilient vents is a design choice after you understand flood risk, not a line the map prints for you. Approved documents and product sheets are not the survey.

Do not concrete over air bricks to “keep the river out” before you know the floor needs that air. You may create the damp problem the Property Care Association would tell you to diagnose properly. Costs of changing vents vary. None are stated here.

What should you ask your surveyor?

  • Are the air bricks clear, buried, or below the outside ground?
  • Is the floor suspended timber?
  • Are you commenting on ventilation, flood products, or both?

What are the typical next steps?

  1. Read the floor and damp comments before you buy flood products.
  2. Use the England flood check only as an area view, and only in England.
  3. Ask a builder who understands both ventilation and flood doors if you intend to change the vents. Get a written scope.

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 air bricks a flood defence?

Ordinary air bricks are vents. They are not certified flood products unless someone specified them as such. The survey usually cannot certify that.

Does a raised path always mean flood risk?

No. It may bridge the damp-proof course or block the vents. That is a damp and timber issue you can see without a river.

Sources