We had a dormer extention done last year for a bathrom. I have just had a fault with the ceiling extractor fan and have taken it out of the ceiling and found that it just vents straight into the roof void, there are vents in the soffets but I am sure this is not the way to do it. How should it have been done. Should it vent via a pipe through the flat roof, and if so how. Thanks
Its not ideal, but its acceptable.
On Tue, 22 Jan 2008 12:16:58 -0800 (PST) someone who may be " snipped-for-privacy@scannex.co.uk" wrote this:-
Roofs, especially flat roofs, should have as few holes in them as possible. Zero is the ideal number, as there are then no holes through which water will probably make its way eventually.
There are a number of ways it should have been done. One of them is shown in
The Builders have stated that the extractor flexible pipe should have gone into the soffets, where there are holes/air vents and it has somehow become detached, can't see how you could have attached it though, the holes are lots of small slits. Is this normal? Thanks
On Wed, 23 Jan 2008 04:01:27 -0800 (PST) someone who may be " snipped-for-privacy@scannex.co.uk" wrote this:-
It is normal to discharge air this way, as is illustrated in the link I posted.
However, the discharge should be through a suitable terminal, which will have a spigot onto which the ducting is connected. The companies I mentioned will have suitable terminals in their catalogues. The small slits are to ventilate the roof space, not to form the discharge from extractor fans. If the builder did provide a suitable terminal you will be able to see it, as it will be a different size/shape to the slots. I suspect you will find that, for whatever reason, they did not install one.
not wide enough for the outlet grill, the extractor pipe is a bigger diameter than the overhang. Thanks for the help
On Wed, 23 Jan 2008 07:01:57 -0800 (PST) someone who may be " snipped-for-privacy@scannex.co.uk" wrote this:-
I assumed that the fan discharged into the original loft, not the flat roof.
There are oblong terminals, into which oblong ducting can be connected, if a circular duct is too large to go through something.
Yes. Often they don't. I have run a flexi pipe to a soffit, and put in a grelle - a special one for the extractor. It was a right bloody fiddle to get it all installed.
Its so easy to leave it out..and because soffit ventilation is vastly overspecified (IMO), and chances are no one will ever notice.
Just discharging into a cold space is a recipe for disater in years to come. Condensation will lead to rot.
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