How do I get rid of this??

[HoopaLoo]

What’s the best way to remove this?
dos this just seem like condensation?

we will be getting extra ventilation but this house was a rental and we now know it’s had issues in the past with previous tenants. This is an external wall of the living room.

No way of us knowing without seeing the property as a whole, from the outside too.
Begin by checking whether there are any leaks from the guttering, any other way that the outside wall could be getting continually wet, or anything from the roof.
How old is the house? If it’s an old house and it’s got gypsum plaster on the wall then it could be that it’s trapping moisture. May need to re plaster that section with lime plaster.
Improve ventilation by opening windows, getting airflow through.
I’d clean the walls with vinegar and repaint, after having done all of the above and see what happens.
Good luck!

I got damp like that on the external walls in my house. It turned out the cavity wall insulation that had been put in before I bought the house was bridging the damp from the outside wall to inside. I had to pay for it to be removed. That helped a lot, but I still get some patches of damp in weird places, but my house does need repointing so that is my next thing to try.

neverwakeasleepingbaby has suggested all the other things I read about whilst trying to solve my own problem.

How old is your house?

1928

it’s been replastered recently the whole exterior

any paint recommendation for once it’s removed?

It’s damp form somewhere. With a gutter, pipe, the wrong type of insulation.

it will fix itself if you enable that eg allow it to dry out. First step is to find the source.

how old is the house? What’s on the outside?

Could it be internal? Previous tenants had no dryer so drying clothes in side. Or is it definitely exterior moisture?

It was built 1928. Rerendered within past 3 years. Not a lime render.

I have this on my bedroom walls. Both on internal and external walls. Never dried washing inside, have vents in the walls, always opening windows and have a dehumidifier. Guttering is terrible as are the fascias. It is structural but as it’s not my property I can’t do anything. I’m in the middle of painting it with Zinsser watertite paint to see if that gets rid of it/stops it. It’s expensive at £68 for a 5 litre tin but all I can do for now.

Landlords always blame damp on tenants drying washing inside. I was told that this was my fault, even though I had a tumble dryer in the garage and used to line dry or tumble everything. When they got the house back they found a leaking pipe and had to hack off loads of plaster.

My house is 1912, one of the damp experts that came out to look for me said I should only get things done with lime mortar or render as otherwise the bricks can't breathe and moisture can get trapped in (I am paraphrasing here so I'm probably not completely technically correct, but thats how I understood it). It's possible that the outside render is letting water in somewhere that isn't able to be evapourated, and so is making it's way in. I have to run dehumidifiers in my house from Nov-Mar to help with the damp as one of my exterior walls runs the whole length of my house and is next to a small alleyway before the next house so it gets no sun on it. In the winter is is wet permanently. It would be worth getting hold of a dehumidifier to try and dry that patch out and then see if it comes back.

Get a damp meter, see where the damp is whether it's rising or descending. Did they use the right render? Re-paint using mould resistant paint, Zinsser, not cheap but it seems to work pretty well.

We’ve got a dehumidifier running. Extractor fans getting installed in kitchen and bathroom next month. Opening windows for at least 10 minutes twice a day.

looking for good products to remove before we repaint

I found both HG mould Remover and Astonish Mould remover to be very good at cleaning the mould off. Make sure you can air the room well though as they both smell pretty strongly!

Once you've sorted it, I'd recommend some
Polycell Stain Block. It comes in an aerosol. I've just used it over a brown dried out damp stain, before repainting.
Worked really well.

HG is good.

I reckon almost certainly structural rather than damp clothes. I don’t have a qualification in damp but I have lived in a few damp properties and now feel I am an expert! 😁