Internal bathroom ventilation

[RusBun]

Do you have bathrooms/showers without openable windows for ventilation and only extract fans fitted - how effective are they at extracting moisture? Do they get mouldy?

We had one it had a timer and a humidity stat on it
so run for a fixed time then after a shower run till the humidity dropped

never a problem with mould

I’ve always kept the door open after finishing up because they don’t seem very powerful. Haven’t seen mould from three of them. Did once put my hand through the wall but that was a basement flat that probably had pre-existing problems. If you can get one with a long timer or that’s connected to the light switch, great. If you can avoid large shower heads, also great. The steam from a large shower head in a bathroom with no window used to make me feel like I was going to black out and in the end I showered with the door open - so try to moderate the water flow.

Extractor fans are never that good tbh. Recently fitted one that's apparently super-powerful and always on in the background. My rainfall showerhead still makes the bathroom steam up, even with the window open. It does clear in a reasonable amount of time, but I was expecting no steaming up at all. Haven't tried it with the window closed though.

You need to look at Part F of Building Regs as it changed very recently. I have just renovated two bathrooms, both with windows. Both showers have ceiling extract within the shower cubicle.

If you are worried about mould, use a specialist finish such as Zinsser.