Flush Ceiling Ventilation Extractor.

[Gill]

A few years ago our bathroom was refurbished and an old, noisy extraction ventilation fan that was sunk into the wall was removed. It was replaced by a ceiling extractor that has a small lip so it does not sit flush with the ceiling. It’s just as noisy.

The problem is that our ceiling is now infested with black mould. I suspect the lip around the extractor is preventing moisture from being sucked of the ceiling surface into the fan. Is there such a thing as a ceiling ventilation extractor that sits flush to the ceiling or is even slightly recessed? I think that might be the solution but I’m also happy to consider other suggestions.

Thanks.

 

[duke]

Possible the issue is there is not enough cavity space in the ceiling so it is sitting low. In which case trimming around it to alluw the cover to fit flush. I would remove the fan first and deal with the mould. Also check to see if it is venting properly by seeing if there is air flow through the vent cap on the exterior.
Can you post a pic.

 

[RogerS]

No, I don't think that that is the reason, Gill. Much more likely that (a) it isn't on long enough , (b) not enough volume being extracted and (c) the room is 'sealed' too much with respect to the rest of the house and so it is not easy for fresh air to enter....which will restrict the outflow volume

 

[RogerS]

It would seem that the AI agrees with me

 

[Cabinetman]

It has been known where lazy/incompetent plumbers just vent into the attic or between floors, I do hope that’s not what’s happened.
I was fed up with pathetic ceiling fans and after talking to my wholesaler friend I fitted a big motor fan thing in the attic which sucked a whole lot out of the bathroom.
As to the ceiling fitting I have never seen a flush one never mind one that’s recessed. But not sure I agree with your thoughts on it’s necessity tbh.
Best of luck. Ian

 

[Lons]

As Roger said your problem isn't the small lip on your extractor cover. You need either a higher volume extractor or adjust the existing one to run longer after you've turned it off. Is it powered when the light is turned on or manually via it's own switch and how long does it run. However if you don't have adequate ventilation or a means of removing the moisture you'll never stop it imo.

I fitted ceiling extractors to our main bathroom over the bath and in the ensuite a combined extactor / shower light directly over the shower, for that reason I powered them both via a pull switch and both set to run on for 5 minutes after use, we also use the windows for ventilation and have very few issues with mould. Both are in line type with the motor in the loft space and of course correctly vented outside. The vent covers protrude probably 15mm.

It does also matter how heavily the bathroom is used. Only 2 of us but very different with a house full of teenage kids.

 

[Gill]

Thank you for some very helpful advice. The extractor comes on when the light switch is pulled on and stops two minutes after the light is switched off. Looking at Roger’s notes, that seems to be far too short a time. Yet it’s longer than when we had the wall mounted extractor!

I’ll look at some online videos and then try adjusting the timer. Hopefully I’ll be able to check that the ventilation is set up correctly too.

 

[Eric the Viking]

My take on this (rank amateur, but I've done five bathrooms now): Run-on should probably be seven to ten minutes at least, and longer in the summer, as there's more moisture in the air then.
Also, as Roger said, make sure there's a good airflow through the bathroom. Ours have fairly large gaps under the doors, which seem to serve, but even then, in the bathroom with the lowest ceiling, the fug clears much faster if the door is left open.

I fit ceiling fans close to, or even actually directly above, the shower area. That works well, as long as the fan is on at the same time the shower is being used. They're usually not strong enough to keep the room bone dry, but they will stop condensation building up.

That said, my best beloved insists that the vent above her favourite shower makes her cold in the winter. She's been known to shower in darkness, just to avoid turning it on, and often forgets to turn it on after her morning shower, leaving the bathroom literally dripping. Guess what: we have black mould in that bathroom quite often.

Don't forget that a mains-powered fan right above the shower is, quite sensibly, illegal. You can either have a 12V or 24V transformer-isolated fan (it must be a remote transformer), or use an inline fan in the ceiling void or somewhere else, with just a ceiling vent in the right place (I've done both).

Also make sure the actual outlet vent, under the eaves or via the roof space, etc., doesn't impede the airflow much - the actual fans aren't very powerful, and don't really like back-pressure or resistance. One of ours is a high-up through-window vent, and unavoidably on a fairly exposed bit of wall: on windy days, you can hear the fan speed change as the gusts come and go.

 

[SamQ aka Ah! Q!]

Get a humidistat-controlled one. Works when humidity is high, for as long as it is high. Try: "Envirovent". Had one now for 6 years, no problems, no mould, no high lecky bills.