How to install air bricks

Posted: 26th April 2023 | Author: Jamie Brown

How to install air bricks

Ventilation is critical for controlling moisture within homes and other buildings. Without a properly balanced system of heating and ventilation, moisture can build up. Ultimately, it can cause problems with damp and mould.

One way of providing ventilation to the structure of your property is with air bricks. These improve the flow of air through walls and under floors, or even within rooms.

But what’s the best practice to follow for installing them? Read on to find out, starting with choosing the right locations.

Where should air bricks be located?

Before you or your contractor can install air bricks in your property, you need to know the best places to put them.

Ideally, air bricks should be positioned below the floor joists. This ensures that the air can flow through the cavity below the floor.

However, the air brick should also be at least 75mm above ground level. This is to stop dirt, leaves or other debris from outside building up and blocking the vents in the air bricks. If the ground outside is solid (e.g. made from concrete or tarmac) then you may be able to get away with having your air bricks a little lower.

Air bricks can be either above or below the level of the damp proof course. Where possible, they should be installed on external walls on all sides of the building. This is the best way to ensure adequate ventilation underneath a suspended floor.

As well as being used to ventilate the space under the floor, air bricks can also be used to provide air flow to wall cavities. You can install them in pretty much the same place. Just make sure the brickwork above is appropriately supported, and the air brick isn’t close enough to the ground that water could penetrate it. This is particularly important if you live somewhere susceptible to flooding.

How many air bricks do I need?

The second thing to decide is how many air bricks you need to install. This could be a job for your builder, damp proofing specialist or other contractor, who will assess the size of the property and its ventilation requirements.

But you can do at least a rough working out yourself, based on factors such as the size of the house and how many external walls there are. It also depends on the size of the void underneath the floor and, lastly, on whether the building has any issues with damp, condensation or moisture.

As a guideline, you’ll need one air brick for every 1.5 to 2 metres of external wall. For larger buildings, it may be better to use larger air bricks and install them around 1.5 metres apart from each other.

How to fit an air brick

After working out how many air bricks you need and where to locate them, you’re nearly ready for installation. This is something you may be able to tackle yourself as a DIY job. Provided you have the skills, tools and of course, the confidence, you should find it pretty straightforward. It’s simply a matter of replacing a brick in an external wall.

But if you’re unsure, it could be best to play it safe and bring in a professional bricklayer or builder to complete the work.

Even if you’re not doing the job yourself, it can still be useful to know a little about the stages involved in fitting an air brick. Let’s take a look:

1. Choose the location and type of air brick you want to install.
2. Drill a series of holes around a brick on an external wall in your chosen location (make sure the air brick and brick to be removed are the same size).
3. Drill all the way around the brick until the holes have been joined.
4. Once most of the mortar has been drilled away, the brick will be loose and can be pulled out from the wall.
5. Lever the brick free with the aid of a bolster chisel. Make sure to pull it outwards, as knocking it inwards can make it difficult to remove.
6. If there is any, remove loose mortar from the hole and clean with a soft brush.
7. Wet the bricks and apply the mortar.
8. Apply the mortar mixture to the top side of the brick and then position it in the hole. You’ll need to make sure you keep it level, or use mortar to level it.
9. Using your remaining mortar, point any gaps which surround the air brick.
10. You might need to apply some finishing touches if the air brick is somewhere visible.

For example, painting or re-rendering around the edges of the air brick where visible mortar is spoiling the finish.

And that’s pretty much it - it’s simply a matter of replacing a standard brick with an air brick.

The Author: Jamie Brown

From my early working life as a labourer, then becoming a builder and a property developer, I have been buying and using building materials for over 25 years. I set about to start a builders merchant which can offer high-quality products and significant savings along with speedy delivery to keep your sites moving. Still having a foot in the construction industry on my own property, I always make sure the products we sell are up to our high standards which is important for us to keep a great image for the company and superior reputation to supply quality!

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