Air Brick Installation

1 Jun 2015
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United Kingdom
Hello forum,
I could do with some advice on how to fix a problem we have with our 120 year old semi-detached house. The rooms at the front get damp and the companies we've had look at it say that two air bricks need to be fitted.

Now since these two companies have been around I've had a closer look at the walls and there are two air bricks already fitted but looking under the floor they are only in the outside wall (not the inner one). Is this normal - it seems odd to me.

One last point - is it safe to remove a single brick (on the inner wall) and replace it with an air brick? I feel nervous about doing that?
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Do you have cavity walls or solid brick? if you are not sure, post a pic of the air vents with some wall around it, you'll get some replies then.
If it helps I have 2 types of airbricks in my 100yrs old house.

Big ones that vent under the floor. When i have had the floor up theres a considerable breeze under there.

Small ones near ceiling level in "the rooms that dont have fireplaces" (pantry, smaller wc, box room).

What kind of damp is in the rooms? Is it condensation and they're suggesting airbricks to aid airflow?

I understand (although have not done it) removing a single brick (on each side) and fitting an airbrick is safe.

More experienced people should giver better advice when you post pics of the wall. Ideally, show the bricks (as the pattern of how they are layed will inform if solid wall or cavity). Maybe also provide a measurement of the wall thickness. I think 270mm or wider is indicative of a cavity.

On a related note, I have wondered (although never asked) what is more expensive: an air brick venting moist air (and heat) outside and the cost of additional heating, or, the cost of a dehumidifier running. The wc is my house has a hell of a breeze through the airbrick which I am meaning to replace with an extraction fan on timer...
What sort of damp? Air bricks to control condensation or for underfloor ventilation?
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We have air bricks on our Victorian property front room, 3 in the bay.
Because the outside level is so high, the air bricks are actually higher than the internal floor level and the bricks end up venting right behind the skirting boards!

As we've redone the whole floor, I've installed 3 pvc flexible ducting ( 15 pound for one meter on Amazon, if I recall correctly) so that the airbricks can actually vent the subfloor.

Additionally I've installed an extra airbricks in the alcove which is north-facing and has seen a lifetime of damp, also equipped with flexible air duct.

When I hacked the bricks out ( drill stitch holes first, then angle grinder then bolster) a lot more bricks than planned got loose ( the original mortar is basically soil) , the house is till standing. That to say that it should be fine to remove up to a few bricks without nothing happening to your building.
Of course if you have a thick cement render, that will help substantially in keeping the house together!

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