blocking up air bricks

[willieboy]

Can i partially block an air brick on the outside of my house?

[happybaggy]

Air bricks are there to provide ventilation under suspended timber floors and it is not recommended you block them off in any way. Don't know why you should want to do this but if is because you are building something in front of it, then move it. If it is because it is in the path of a strong prevailing wind then fit a cowl over it. Cowls can be obtained from most good builder's merchants or on the web from a company called bes.ltd.co Hope this helps

[willieboy]

thanks for help, to be a little more precise, i am putting some decking down, and the required level will mean half the air brick, 2 out of 4 horizontal rows, are covered. the other 2 layers of holes remain unrestricted. will the air flow be enough to do its job!?

[heathfield]

The effectiveness of the air brick will depend on the direction of the prevailing wind. But air bricks are set above ground level so that splashwater from heavy rain doesn't get into foundations of the house. With your airbrick at decking level, this could happen.
There are extenders that raise the effective height of an air brick to prevent rainwater entry, and that could conceivably be fitted externally. See an example here.

[gasman]

There may also be a Gas appliance that needs the porpose provided ventilation and just blocking one hole never mind half of it could reder the applaince dangerous. If it is not getting the correct amount of ventilation, then incomplete combustion happens and then you're getting poisoned.....