Mould despite extractor fan

[zaffa]

The extractor fan in our bathroom stopped working about a year ago. I finally got around to getting it replaced about four months ago, and ever since then I've noticed mould on our bathroom ceiling.

I'm really confused by this, isn't the fan supposed to stop mould? We keep the bathroom window open a lot, and run the fan with every shower, so I can't figure out why suddenly mould is growing over the ceiling?

We've cleaned it and repainted with anti mould paint but I don't know if it will reappear (we've cleaned it already a few times). Does existing mould encourage more mould?

I read that undiluted white vinegar actually kills some forms of mould, the mould remover doesn't. How long does your new extractor fan run for when you leave the bathroom?

I switch it on and off, it doesn't ever turn off automatically.
Maybe that's the problem - how long should it run for? It's usually just on when the shower is on

It should be running for quite a while after the shower. Our one has a humidity detector and automatically keeps running if the air is still damp.

We don’t have an extractor in our bathroom but really need one. We had an issue with mould on the ceiling and I think the spores can multiply.
we’ve solved the issue by making sure we have the window open at all times and particularly when showering. I cleaned all the mould with black mould remover and then applied an anti mould treatment which supposedly kills the spores. I coated the whole of the bathroom ceiling.
Then I painted the ceiling with bathroom ceiling paint.
im also using a dehumidifier which is massively helping which is on the landing right outside the bathroom.

i think extractors should keep running for a while after you’ve used the bathroom as it needs to keep removing the moisture from the air particularly after showering

Ours goes for about half an hour after a shower

Apparently you need to keep the bathroom door open while the fan runs.

Bathroom extractors work better with the door and window closed and dry air untering through the gap u der the bathroom door. Water vapour is ligter than air and will rise towards the ceiling where the fan can suck it out i stead of blowing around and mixing.

Also check the loft insulation above the bathroom ceiling.

Many bathroom fans are too weak to cope with steamy showers unless run for very long periods. The cost of their electricity is negligible.

We have had problems with this in the past. You need the fan to run for longer, and in our case we also left windows open too.

But the real issue was that the loft insulation we had recently installed was directly over beams with some of the bathroom spotlights and was preventing some of the previous ventilation flow upwards. We moved it and the problem largely went away.

I can't recommend HG Mould Spray strongly enough! It just zaps mould! An extractor fan on its own probably won't stop mould. I found it's important to run it during the shower and then leave it running and open the window (together it creates cross ventilation) until walls, ceilings, windows are 100% dry. I also wipe dry with a cloths (several cloths indeed, as they get wet) all tiled wet surfaces and window panes (window vac works great for that, too). We have a lot of bathrooms, but as it's so te intensive to get it all dry, we only use 1 in winter, and every 2 days I line everyone up to have their shower/bath one after another so that I only need to clean and dry once 😂

Thanks everyone.
And for whoever recommended it, we have e HG mould spray and I do agree - it's fab. However I would rather we didn't get mould at all, we never used to. However thinking about itv the reason I was prompted to fix the extractor fan is because teen DSS moved in with us full time and started taking very long, very hot showers which left the bathroom dripping.

I think we don't run it long enough. I could kick myself for actively deciding against the one that comes on automatically 😡.

I will give it a go running it with doors and windows closed for a very long period of time, and maybe also try drying off the walls a bit. The whole room is tiled except the ceiling, and I do see a bit of mould edging in the grouting, but otherwise it's just the ceiling affected.

Thanks all

Do you know the make and model of your fan? Or post a pic.

Is it in the wall or ceiling?

It's a ceiling fan - it's just the basic wickes model - it was about £16. It comes on when the electric shower comes on (which we don't use anymore) so we just switch it on and off when we shower. When it stopped working it was the motor I think so we just switched like for like.

The budget models are not very powerful, and not adequate for steamy showers, you might have to leave it on all day to dry the room out.

Is it attached to a duct in the loft, that blows the steam out through a wall or the roof? It may be possible to change for a better one.

Agree with Piglet John about checking the insulation over the bathroom, if the ceiling is freezing then you're much more likely to get mould growing there. Also consider upgrading to a better spec fan. Blauberg do one which is 27 or 28l/s which is significantly better than your bog standard Wickes one (which could be as low as 6l/s. Building regs require a 15l/s minimum in new bathrooms.

Meant to say, the blauberg fan will fit the same duct size as a standard fan. Most fans which extract more will need a bigger hole.

Sorry to jump on your thread OP but we're having similar issues.

Would you recommend a Soler & Palau SL SD100 @PigletJohn? We currently don't have any extractor in the bathroom.

I don't recognise that model number. If you have steamy showers, I usually recommend a ducted inline fan (fitted above the ceiling in the loft usually) around 240 cu.m/hr such as
www.tlc-direct.co.uk/Products/SLTD250SILENT.html
It is a fairly expensive brand but I find the quality very good, and their fans are very quiet.

That one fits the common 100mm duct suze. Rigid duct is better than the convoluted hose. It can also be used with 125mm duct, which gives better airflow and will fit a bigger fan if you ever want one.

Cheaper brands are available.

Most builders fit a fan of about 80 cu.m/hr capacity, which is fine for a WC and just about adequate for a bath if you run it long enough.

As these fans are very quiet and use little electricity I favour letting the light switch turn them on every time the bathroom is used, and setting the run-on timer so it will continue ventilating the room after you leave.

I used to describe them as inaudible, but I now realise my hearing is poor so I am not a good judge,

Oh, you meant one of these
www.tlc-direct.co.uk/Products/SLSD100.html

Not powerful enough IMO.

If you have no room for a loft fan, and must go through the wall, you will need a larger one to get enough throughput.

This 6 inch one would probably do, it seems to be just the usual design upscaled, but is not as quiet. I have not used one. It is quieter than the large Xpelaire extractors you may have seen in kitchens.

www.tlc-direct.co.uk/Products/SLS300CRZ.html

Thank you very much as always @PigletJohn, I'll speak to our electrician about the loft fan, hopefully it will be possible.

Would the larger wall fan you linked work in kitchen? We don't have a functioning hood at the moment and don't plan on replacing it at the moment as we're planning to renovate soon.

Can't see why not

Though kitchen fans do get greasy and need cleaning, the ones I linked do not have a filter or anything. I think I've seen some that do but it is not common. They might be listed as Kitchen Fans but I can't see one.

@PigletJohn thanks for the ventilation recommendation. Could I ask if you could similarly recommend a quiet and effective shower pump? There is a very wide range on offer!

@PigletJohn can you recommend a window extractor fan for our hideously mouldy ground floor bathroom? Or any other suggestions?

Window fans seem quite rare now, and I can't see a window kit for the ones I like. More usual is to have a hole bored through the wall, as high as possible while avoiding lintels. There are special tools for this that plumbers and electricians use (also used for pipes). You can hire them but the drill is very big and heavy and not recommended if you are working off a ladder or inexperienced. The minimum size is just over 100mm diameter but if you have steamy showers you will need bigger, or the ducted type.

If you already have a window with a hole cut in the glass you can still get a few fans to fit. Quite likely it will be six inches or more. If it is double glazed you have to buy a new sealed panel made to order.

P.s. if you have a high airbrick (old houses often do, to ventilate the original store cupboard) there will be a rectangular, lined hole about 9" square, and these are sometimes used with a fan fitted in a piece of thick plywood mounted in the hole.

90% of houses I have been inside have the same model of fan (white with the 15 minute activation). I swear that they do not work. I am having ours ripped out and going back to the older type which definitely performed extraction effectively.