Mould in apt, not sure if my own fault, how to deal with Landlord?

why dont you wash it with an anti fungal cleaner to kill it and then BIN primer it to cover the discolouration.

BIN is great for covering stains. dries in minutes but bloody stinks. 123 works as well but not as well but it is water based and doesnt stink. a few coats will block the stain.

How much mould are we talking about?

You said at the start that it's 'a bit under the windows' but the rest of your post reads as if the walls are covered top to bottom throughout the whole room..?

If it's just a bit under the windows that's not an issue at all. We live in a very damp country.

I don't get why you would feel the need to cover it up before the landlord gets there.

Mould origins are varied, a lack of sunlight, drying clothes inside, or a leak/ damp of some sort could be causes.

Best to address with the landlord so they are aware it continues to be an issue, as a LL, I would prefer to know so I can establish the source of the issue before it gets any worse.

i would assume so. most hardwares , co ops, paint shops b n q , screfixs shops will have it. get a small tin unless you need that much. it goes a long way

If not new, just clean it.

This stuff is quite good

No harm thinking about getting a dehumidifier for the longer term after all of the above are sorted or else you are not tackling the root cause.

You could also check around the inside and outside window pane does it need a bit of silicone? They're straight forward to use, lots of youtube videos online. The gun and silicone are fairly cheap.

He might appreciate it more if you make him aware of the problem so that it can be fixed. Tell him what you've done to try and fix it.

If it's just directly under the window sill it might need silicone around the frame on the outside, but I would let him do that.

If you try to cover up a mould problem it can turn a minor problem into a major one.

Most house in Ireland will get mould behid curtains under a window if they are kept closed all the time.

The mould will be in the curtains too, so even though you might not be able to see it it will transfer to the wall.

You are doing the right thing cleaning it as soon as you see it because if you leave it it will spread all around. Even through the air to other rooms and walls.

So attack it every time you see it. Maybe replace the curtains too the next time you kill the mould. Then open the curtains and windows regularly. And at the slightest sign of mould in future treat it. And make sure you dont dry clothes inside. Sure way to get mould in the house, and not always in the room you are drying them in either.

You should follow the advice here and clean it properly at any sign of it and get a dehumidifier.

Otherwise it will be in your wardrobes and everywhere else before you know it and it will be too late then.