Installing Extractor Fan to an Air Brick?!? Eeeeek!

DIYSparky · Posted: Tue Oct 16, 2007 6:48 pm

Hi,
I'm installing an extractor fan in a bathrrom that previously only had a an air brick and a louvre ventilator (is that the right name? Some slots that are always open). However I'm struggling to know the best way to do it, any advice would be very much appreciated.

The diagram shows roughly what the situation is. The pink colur is where the ventilator used to be, it's now been removed and just the hole is there. The blue bit is the air brick. The green bit is mortar or something similar. The red bits are brick work. I'm on the 3rd storey of a block of flats so accessing from the outside is effectively impossible for me.

Can anyone advise what the best way of installing the extractor fan would be? Is it possible to connect the ducting from the extractor fan directly on to the airbrick so I don't have to drill through the brick itself? I don't have the drill accessory to drill a 100mm hole through the wall so would have to hire or buy one hence I'd prefer not to if at all possible.

Much appreciate any help you can offer.

Cheers,
Aaron

noseall · Posted: Tue Oct 16, 2007 9:50 pm

you can successfully vent the fan via the airbrick. it will be more efficient if you pack insulation around any voids that are not part of the ducting apparatus.

in other words, if you stick a 4" pipe up to a 9"x9" air brick fill the void surrounding the pipe.

JohnD · Posted: Tue Oct 16, 2007 9:54 pm

When I did one I used a piece of WBP to fit the hole in the wall, with a hole in the middle to fit the fan.

There was enough room in the thickness of the wall to put the bit of board and the fan inside it, and just have a grille showing.

DIYSparky · Posted: Mon Oct 29, 2007 10:05 pm

Thanks, I've got some flexible piping and some insulation stuff left over from insulating the inside of some stud walls. I'll give it a go.
Thanks for you replies.
Aaron

daytona · Joined: 02 Nov 2007 Posts: 697 Location: United Kingdom

use a piece of solid duct inside the void for the airbrick and pack some insulation round it so it doesnt move about.put a backdraft shutter on the ducting so the air can only pass in one direction.nothing worse than cold air coming through the front of the fan when its not in use.or alternatively,use a centrifugal fan

ModernMaterials · Posted: Sat Nov 03, 2007 8:38 pm

my 2p's worth:

Temporarily fix the vent up to the airbrick and insulate with aerosol foam

yorkshirelad · Posted: Fri Sep 09, 2011 1:47 pm

Hi, I have just had exactly this done in my bathroom, I wondered what sort of insulation i should pack the void out with. I have some left over standard loft stuff, or should i go for something with a little more rigidity (and humidity resistance?) like the kingspan board or polystyrene.
Cheers

Perry525 · Posted: Fri Sep 09, 2011 5:12 pm

If you have a clay air brick, it is best to set the outlet some way back from the air brick to benefit from the extra holes, this will save the load on the fan motor.
As its a bathroom, whatever type of fan you fit, be it with shutter or not, it is a good idea to fit an airtight box, with an opening door, to stop those nasty drafts when the fan is not in use.
Also keep in mind that, the fan needs to pull air from somewhere to expel with your water vapour, a better idea, but more expensive, it to fit a fan with a built in heat exchanger, this will ensure that the fan does not struggle and does not cause drafts elsewhere.