Bathroom mould advice please

Unhappywife

I’ve black mould appearing around a bathroom window. The window is opened when showering and there is also a small fan in the bathroom. I’ve had it repainted a few times with mould paint but it keeps coming back. What do I need to do? Thank you.

Metric Tensor

There's a cold area in that location on the window reveal.

The correct way to do things would be open up the window reveal and find out what's causing the "cold bridge" in that area then fix the issue, cover it back up, skim it and then paint again.

That's not a huge job but still involves disruption. In the meantime the best you can do is keep the window open more of the time and the fan on for longer and try to keep good ventilation going through the room. Then attack the area with anti-fungal spray and scrub it fairly regularly.

Calahonda52

Given that its a small enough area, you could consider removing the mirror and dry lining the reveals , head and the wall above with a thin piece of insulation, on plaster board, sealing it around the frame and ceiling, this will increase the wall temp enough so as to stop the water vapour condensing out on the coldest surface in the room.
It does not address the removal of the water vapour which is what MT suggests.
Improve the fan as well, and maybe partially enclose the top of the shower to restrain the water vapour from wandering too far before the improved fan shifts it.
Also check the ducting for the fan if in an attic.

Unhappywife

Thank you so much. I will have a look at those solutions. The mirror is a recent install - wish I had sorted it out beforehand.

Calahonda52

Unhappywife wrote: »

Thank you so much. I will have a look at those solutions. The mirror is a recent install - wish I had sorted it out beforehand.

What material is the white beading inside the window frame, were the windows upgraded?

Unhappywife

Calahonda52 wrote: »

What material is the white beading inside the window frame, were the windows upgraded?

The windows were replaced to pvc about 12 years ago before we bought the house. The little pieces are wooden bits sealing around the new window I guess?

Calahonda52

Unhappywife wrote: »

The windows were replaced to pvc about 12 years ago before we bought the house. The little pieces are wooden bits sealing around the new window I guess?

May have been fitted if the window was slightly too small for the opening or to avoid patching with render.

They will need to come out to get the insulation in close, may need a bit of patching up first.
It ie essential that the window frame / wall joint is airtight before you add any insulation so maybe take off a small piece first to scope the scale of the work.

Its all very doable, just care and attention!