Mould growth - how is this appearing here

[B Souza]

Hi,
I'm having mould growth happening on this part of the ceiling. It's the front facing bedroom which has a flat roof above. I live in a mid-terraced house.
Any suggestions what is causing this and what can be done to get rid of this? I've used mould remover, but it just keeps coming back.
The paint is also flaking now. Should i paint it with a gloss paint so that I can wipe it down in the future (although a gloss paint would smell for longer making the room uninhabitable for my kids)? or is there something else which can be done for a permanent solution to this.

TIA.

 

[stem]

Does the flat above also have a bay immediately above yours, or does your bay protrude from the building and have it's own roof, something like this?

 

[B Souza]

This is on a first floor. There is just my roof over me. However, this part where the issue is, is protruding from the facade and the top is not tiled. It's flat and I guess there's this bitumen felt on it.

 

[endecotp]

Most likely, that is the coldest point on the ceiling and you’re getting condensation.

Do you have bathroom and kitchen extractor fans? Do you dry clothes on radiators etc.?

 

[B Souza]

Just a bedroom. There's no extractor fan, nor do i dry clothes there.
Do you think getting the flat roof re-felted would stop this? or is this some other problem? Is this a DIY job (to re-felt) or do i need to hire someone. Any guidance on costs if I need to hire a tradesman?
Appreciate all your replies

 

[endecotp]

Do you have (and use) bathroom and kitchen extractor fans in the bathroom and kitchen respectively? Do you dry clothes on radiators etc. anywhere in the house?

Re-felting might be appropriate if there is a leak. But if the issue is that it is cold, you need to add insulation.

 

[JP_]

Probably a lack of insulation in the flat roof, so the ceiling gets cold, condensation forms and then mould.
Is there a radiator in the bay? Keeping the heating on all the time might help keep the ceiling warm and dry enough to prevent future mould growth.
Only long term solution really is to ensure the ceiling / roof is insulated enough to prevent condensation.

 

[B Souza]

Yeah, I do have a bathroom extractor fan. Kitchen is on ground floor and has extractor fan. Clothes dried close to a radiator, not on it though, on ground floor.

Cool, might have to check re-felting next summer then. Thanks for mentioning insulation. Will check this with a trademan. Would this involve adding insulation from above i.e. externally? or would i need to cut a hole in that ceiling and add it from inside the bedroom? Thanks again.

 

[stem]

the top is not tiled. It's flat and I guess there's this bitumen felt on it.

That's what I suspected and why I asked the question, because I had exactly the same situation in a property about 20 years ago. I cured it by making a 4 small holes in the ceiling above the bay and injecting a couple of cans of expanding foam through so that it filled the void between the plasterboard and roof and acted as insulation. That's probably not an ideal way of doing it and I'm sure it might have caused a problem later down the line if it ever has to be gotten rid of. The professionals on here might be able to offer you a erm...... professional solution.

Anyway, the new owners have built a tiled roof on the bay now.

If there is a leak then that would need to be sorted first, but looking at the distribution of the mold it looks more like it's caused by condensation.

 

[endecotp]

The professionals on here might be able to offer you a erm...... professional solution.

You might like to ask in “floors roofs and lofts”, rather than here in plastering, to get a useful answer. I guess they’ll want to see what it looks like from above.

 

[foxhole]

You appear to have a downpipe and gutters where the mold is, have you checked its not blocked.

 

[endecotp]

You might like to ask in “floors roofs and lofts”,

Sorry I was confused when I wrote that. There are two forums, “floors stairs and lofts” and “roofing and guttering”, from which I somehow managed to invent “floors roofs and lofts”....