Mould problems in bathroom and getting worse

[detoxingblend]

I’ve been dealing with some mould problems in my bathroom. I think this was due to no ventilation apart from a small window. There was also a hidden leak under the bath which has now been fixed. It doesn’t help that the previous owners used cheap paint, but I’m having the room repainted soon with proper stuff.

The outside wall has always had some mould patches, but it seems to have got worse since the fan was installed. I thought the fan was just pulling out all the moisture, so not necessarily a bad thing, but now I’m starting to worry it might be something else. Does anyone have any idea why this could be happening?

The fan is in the ceiling above the shower and goes through the loft, venting the air out through a small vent on the side of the house - photo attached. The electrician knows his stuff (been a sparky for over 20 years) so I have no reason to believe that it wasn’t installed correctly, but I’m confused as to why the mould situation has escalated. Any thoughts or advice please?

No idea from a building point of view sorry but some plants thrive in bathrooms and are known to purify the air and help to reduce mould.
Spider plants, Peace Lily and Snake plant are all examples.

Interesting, I didn’t know plants could help. Thank you!

I’m curious if painting the room with anti mould paint will prevent it, since I assume there isn’t a “barrier” on the walls or ceiling at the moment.

My friends bathroom is like mine, with a small window and no fan, but she has proper paint and doesn’t get any mould.

The outside wall has mould? Is it a north facing wall that just stays cold and damp? It shouldn't affect the inside of the house, I assume it's a standard cavity wall construction. And I assume the vented air is through trunking all the way from the bathroom to the outside vent? You can paint the bathroom with mould resistant paint (quite expensive, but is good), ventilation is most important so the fan should help a lot, it will take a bit of time for it all to dry out properly if it's been damp for a long while.

Edit the picture of the outside was confusing me I assume you meant the inside of the outside wall!

Are you closing the door and window when the fan runs? Ideally the fan needs to run for 20 minutes after a bath/shower with the door and window closed.

Sorry for the mix up! What I meant was that the inside of the outside wall has mould. The picture was just to show the vent. I'm not entirely sure on how it's set up, but I know it passes through the loft and then pushes the air out of the vent. I'll double check with the electrician though!

Yep, the door and window are closed. I usually run the fan for around 2 hours after taking a shower as well.

We had a window permanently open and mould problems and assumed it was bathroom moisture but it was actually roof problems which were over that corner of the building.

This type of set up is not as good as a fan that vents directly outside. That is because as the steam rises up your vent in ceiling it turns to water vapour and can drip back down pipe so not actually all vent out. In your position I'd tank the walls with aqua plaster board and either tile or add bathroom boards over the top. I'd move fan to vent directly out of wall. I'd use a dehumidifier to suck water out of walls before I did anything else and yes Spider plants and peace lilies also absorb moisture from the air. If this bathroom is next to a kitchen make sure the door is always closed because it could be getting condensation from kitchen. Always use a lid on all pans, always use extractor fan in kitchen when using hob, never dry washing over bath as that causes damp.

Thank you! I really wish I had insisted on having the fan vented through the wall instead of the ceiling. I can't remember why the electrician didn't or couldn't do it. Unfortunately, I just had it installed a few weeks ago and I'm not really in a position to spend more money to have it moved.

The kitchen is next door, but I always keep the door shut with the window open (no fan) when I'm using the hob. However, I don't do that very often since I mostly use the oven and air fryer.

I'll definitely check out the plaster boards though. I'm open to trying anything at this point, well, except moving the fan.

I'd run a dehumidifier all day for a week or two, really dry out after the leak. The amount of water collected should gradually reduce if it's just drying out and there isn't an ongoing issue. If it doesn't, you know you need to investigate further.

Our downstairs bathroom was plagued with damp, previous owners covered walls with thick pink gloss paint to hide it. fast forward, we took walls back to bricks, damp proofed, etc...but what made a difference was installing a huge extractor fan, the small 5 inch ones which everyone has are pretty useless, we have a 10 inch thing which is super powerful and now no mould issues.

An aero 360 might help too if you don’t have an electric dehumidifier.

Check the roof and gutters! We had a problem with mould, the gutters werent pointed properly and were causing mould.

Dehumidifiers are amazing. We had terrible mould problem in our bathroom but having the dehumidifier on while we bath/shower and leaving it on after for a while has completely solved it. We have a Meaco.

Nope, not good enough for this problem

QVC have a dehumidifier for £20 a month x5. They have a 60 day policy to try things out and if you don’t like you send them back for whatever the postage costs.

I don’t have any fancy paint or wall boards etc and my bathrooms never mouldy.

so why is yours??? It might be being caused by something else?

Maybe there is a leak in the vent tube and water vapour or water is going down the inside of the cavity wall ?

paint won't cure the issue. Prevention is all about temperature and ventilation.
Either heat the room or ventilate it.
You say small window, but how long do you have it open for?
our family bathroom has never had mould but we leave the window open all the time

We have the same setup and have to have a dehumidifier in the bathroom.

Can you take some photos of the setup in the loft, please, and the grille in the bathroom ceiling.

A ducted fan in the loft can be very effective, and quiet, but it's possible something has gone wrong or yours is not powerful enough. Your bill may say what was fitted.

Long steamy showers do cause a lot of damp.

I see the exterior is a modern cavity wall so should not be very cold, especially if it has CWI. I can't see damp from a gutter or overflow on it.

Oh, and if you are willing to let a smoker into your home, make them stand under the grille and see if the smoke is visibly sucked away.

If not, buy some joss sticks.

Sounds like my bathroom. I also never dry washing around the house and limit the use of the tumble dryer. If its clear outside the washing is going out.

What fan was installed? We upgraded our shitty bathroom fan to an inline fan which is a larger and so has to go into the loft space. Having seen a lot of instals via youtube sometimes the ducting from the fan to the outside wall is done with flexible ducting which isn't anywhere near as good as rigid pipe. I have also seen in houses we have bought the fudging that goes on with venting just anywhere into the loft. There are limits on what a fan can pull air wise depending on how far the air has to travel to the outside vent.

Secondly, can I recommend a window vac? Our is a Bosch one but the most recognisable one is the Karcher. The sheer amount of water from the walls of a shower it removes will help with the condensation left in the bathroom. It takes under a minute to hoover all the water off the walls of our shower cubicle every day. I also vac the shower tray too to get rid of everything. Then a quick wipe with a towel.

Came
on to say a dehumidifier too. And dry the room out for a few weeks with a an industrial fan heater and a dehumidifier. You can hire them from hire shop. We had a leak they insurance provided them and they were amazing.

we just have a normal non industrial dehumidifier from lidl- I think is russel Hobbs and it’s amazing the amount of moisture it collects when I dry laundry.

paint won’t stop the mould but it will slow it. When you do paint you need stain blocker first then the anti mould paint . Keep the bath panel off too to ensure it is dry under the bath.

to target Mould in the shower use bleach and cover with toilet paper to make a poultice.

Oh, and stand outside while the fan is turned on and off. The flaps should blow open when on, and flop back under gravity when off

(They should also rattle annoyingly in gusty wind, but that is a different issue)