Yellow mould spots that spread like wildfire.. what is it?

[TulipVictory]

When we moved into our house 5 years ago, the house wasn't very well kept and most of the walls had mould. Upstairs, there seems to be this yellow mould that reappears every year as soon as it gets colder, it is speckled.. one day I wake up and all of a sudden the whole wall is covered in yellow spots. The only way to describe it is like a rash of spots everywhere! It's not just the walls but also the doors. I can't get a very good picture of the wall because I've just scrubbed it with the HG bleach spray but even so, it hasn't completely gotten rid of it... I can still see the spots they are just faded.. it's basically small yellow blobs everywhere! Does anyone have any idea what kind of mould this is and how best to get rid of it.. I have a photo of a few spots on the door that I haven't scrubbed yet..

Following as we have this exact problem

If they are only on wood, I would have said they were knots in the wood that weren't fully seasoned and leaching tannin. We get them on some of our newer pine doors. But if they are coming through plasterboard, I don't know what to suggest.-

What about this?

Epicoccum nigrum is a fast-growing, yellow mold that can be found in or on damp drywall, mattresses, wood, carpets, and furniture. It ranges in color from yellow to orange to brown depending on conditions and surroundings.

What is the ventilation like in your house? Lack if ventilation is a common cause of damp and mould

@MintJulia no it's all over the plastered walls as well 😰

@MintJulia we don't have vents on our windows , I do try to crack the windows but it is difficult with the colder weather and increased cost of heating. There's definitely been condensation on the windows themselves the last few weeks

Sorry that was meant for @Yucca78

I think @MintJulia has the answer. Ventilation and heat is the answer as dry, air stops mould growth. Could try a dehumidifier, but opening windows for ventilation is cheaper.
could try those anti mould paint when redecorating. Tbh, you may be looking at new doors and plaster (replacing whatever is infected) if it’s allowed to continue. But prevention is always better and cheaper than the cure.

I live in an old house.......the answer to our damp was simply opening windows. I usually leave them on "open locked "

My bedroom window is hardly ever locked

Soot can leave yellow patches?

Old houses need to breathe. Especially ones that have solid walls (ie no cavity).
Ventilation will help, and also removing non-breathable materials like non-lime render on the outside, cement pointing, modern plaster, modern emulsion paints etc.

Ventilation.
We found some high-viz-yellow mold here under the wallpaper in one room. Not like yours, much more luminous and in one huge patch. Took the advice of a landlady we met who said tenants who blocked ventilation sometimes got mold, she would advise them to ventilate the place peoperly rather than blocking up vents, and that always worked, but to get rid of the mold itself she used Dettol mould remover spray because she had found that using other products got rid of it but it would come back. She said she'd not had it come back once sprayed with that stuff, provided the tenant kept the vents clear. I used it, and we keep the house properly ventilated. That wall is painted (so no paper to cover anything up) ad the mold has never come back.

Aye, on our lime walls, like the one I mentioned above, I use breathable claypaint.

The entire world is full of mould spores, everywhere, all the time.

They will grow if you provide them with moisture and a comfortable temperature.

Common ways to provide the moisture are damp washing inside the house, and insufficient ventilation, especially in bathrooms, kitchens and bedrooms..

Less often there is a building defect such as a plumbing, rain or roof leak.

With all the dimwitted advice in the media about keeping warm by stopping up every draught or vent, I am anticipating about three new threads a day on this come February. And similar re that mythical creature 'rising damp'.🙄
It makes me cross that people are being misled. Quite apart from the fact that a damp house (which is what you get if you fail to ventilate) will feel a LOT colder than a dry one at the same temperature, as well as being far less healthy, it's bad for the house.

@TulipVictory

Older thread but did you get rid of it