Anti-Flood Air Bricks: How They Work, What They Cost And Whether You Need Them

Check your flood risk band first at check the flood risk of any UK postcode. Air brick protection matters for homes at risk of river, sea or surface water flooding. Partner links below are labelled and marked as sponsored.

---

What Is An Anti-Flood Air Brick?

An anti-flood air brick is a replacement for an ordinary air brick that seals itself against floodwater. Air bricks ventilate the space under suspended floors and inside walls, and without protection they are one of the easiest routes for water into a home.

Two main options:

GOV.UK lists "self closing air bricks" among the flood protection products homeowners can fit before a flood.

---

How Does An Anti-Flood Air Brick Work?

A self-closing air brick shuts its ventilation holes when floodwater rises and is otherwise open, so it ventilates in dry weather. A cover works by physically blocking the brick's openings once fitted.

What each does in practice:

1. Dry weather. Self-closing air bricks stay open, so underfloor ventilation continues. Demountable covers are stored; permanent covers restrict airflow.
2. When water rises. The self-closing brick seals without anyone present; a demountable cover must already be fitted.
3. After the flood. Historic England notes self-closing air bricks Smart airbricks are a passive measure that can replace existing air bricks. They will shut off the ventilation holes when floodwater rises but will require being opened again once the flood event has passed, and permanent covers need to be opened and cleaned.

Ventilation is the trade-off: underfloor voids need air to stay dry. Removing demountable covers after a flood, as Historic England advises, lets the space dry out.

---

What Does An Anti-Flood Air Brick Cost?

Self-closing air bricks cost more than basic covers in the Environment Agency's evidence. Environment Agency evidence priced air brick covers for a typical home at £180–1,680 (assumes 12 per property) and automatic air bricks at £1,550 (assumes 12 per property, includes installation), at 2007–2008 prices.

Source: Environment Agency, Cost estimation for household flood resistance and resilience measures (2015), citing 2007 prices. Current prices are higher. The number of air bricks varies by home.

What air bricks are advertised at in 2026, per unit. Because the Environment Agency figures above assume twelve per property, they are hard to compare with a shop price. Per unit, suppliers publishing their own prices list a removable cover at £30.00 for a single airbrick cover, £60.00 for a double, an automatic air brick at £70.00 for an automatic airbrick that closes as water rises, and an anti-flood air brick at £74.17 plus VAT for an anti-flood airbrick, supply only or supply and installation.

Checkatrade's cost guide (Last updated: June 2026), which includes fitting, says costs start at around £15 and increase to £50+ for more hardcore options.

Prices read at each supplier's own page on 17 September 2026 (Floodgate, Flood Protection Solutions). Naming a supplier is not a recommendation and no link here is paid. Multiply the per-unit price by the number of air bricks in the property, and add fitting for the automatic types.

---

Which Anti-Flood Air Brick Is Right For Your Property?

A self-closing air brick is right for a home that may be empty when flooding starts or where fitting covers is impractical; covers suit homes where someone can fit them after a warning. Very old or historic buildings need advice first, because ventilation matters to their fabric.

Certified products are preferable: government-funded schemes require that products must have a British Standards Institution (BSI) Kitemark or hold equivalent certification.

---

How Do You Fit An Anti-Flood Air Brick?

An anti-flood air brick is fitted by removing the existing air brick and bedding the new unit into the same opening, which is building work best done by an installer. Covers are simpler: a frame or fixing is attached around the brick and the cover fitted when needed.

Steps:

1. Count every air brick, including those on hidden walls and extensions.
2. Check the ventilation needs of the underfloor space with a surveyor.
3. Replace or fit covers to all bricks below the likely flood level; one unprotected brick defeats the rest.
4. Seal around each unit so water cannot pass the frame.
5. Test and maintain. Check them regularly; FloodReady found that many people feel that PFR products are "fit and forget".

---

Does An Anti-Flood Air Brick Reduce Your Insurance Premium?

An anti-flood air brick does not automatically reduce your premium; each insurer decides whether protection counts. The ABI advises owners to Check first if your insurer is able to take surveys into account when assessing whether to insure your property. Keep product certificates and invoices.

A 2021 government consultation on Flood Re proposed that Flood Re could offer discounted premiums to households with protection such as airbrick covers or non-return valves; check the scheme's current terms with your insurer. Build Back Better, after a flood claim, can pay for resistance measures during repairs: Flood Re's examples include carrying out surveys to understand the flood risk and potential mitigation, the addition of flood resistance measures such as flood doors, and flood resilience measures such as the replacement of damaged parts of the home with more flood resilient materials such as hard floors.

---

What Are The Alternatives To An Anti-Flood Air Brick?

The alternatives are to fit covers instead, raise the level of air bricks above the expected flood depth during building work, or accept water under the floor and use resilient materials. Air brick protection usually works best combined with door protection and non-return valves.

• Flood barriers and flood doors — protect the other main entry route.
• Non-return valves — stop water returning through drains.
• Resilient floors — concrete or sealed floors limit damage if water gets under the floor.
• Sump pumps — remove water from underfloor spaces.

How these fit together is in property flood resilience.

---

Sources (Verified 17 Sep 2026)