Advice on ducting kitchen extractor fan through air brick

13 Jul 2018
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United Kingdom
Dear DIY Not community,

Wonder if any plumbers, electricians or kitchen fitters could advise me on best way to duct kitchen extractor fan through and existing airbrick in my flat.

Should be able to view some pictures from the following link (click them to enlarge):

Image 1: Final kitchen plan. Extractor will be installed into the middle wall unit.
Image 2: Picture of the same aspect
Image 3: Air brick from inside with dims
Image 4: Air brick from outside with dims

My plan will be to run rectangular manrose ducting flat along the wall, taking 45 degree turns around the column and behind right-hand side wall unit to the centre one for connection with the extractor.

Manrose ducting:

I would welcome advice on how to achieve this, specifically how to duct through the airbrick to the outside. It’s a cavity wall so aware it needs to be air tight connection.

I’ve seen double air brick ducting adaptors but the dimensions don’t seem to be compatible. Some examples here:

Any help on this gratefully received.

Many thanks,

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The inside is just a plaster part and i would think just comes off first with a bolster, And then i would just cut all the inside fins off with an angle grinder, place pipe and fill in with brick, The other way would be to remove it (possibly have cavity beads or insulation fall out) and brick it up and use a core drill for a round hole or leave a gap for the manrose-square

Not an expert.

To get it flat to the wall you would be better of bricking it up and cutting a new hole manrose channel sized / core drilling.
Last edited:
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some people have different opinions, but I would keep the ducting as large as possible especailly on a long run. Also I found acrylic sealant is good for sealing and sticking ductwork if you don't want the air blowing where it shouldn't.

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