Which stain block for this?

Hi,

I have 2 stains on the wall at the top and bottom inside a bedroom wardrobe and I was wondering what I stain block I should use to cover it. I did put some Thompsons Stain Block Damp Seal on it years ago but it came back after a couple of years.

I was thinking a Zinsser product but not sure out of BIN, Cover stain and 123? The area is dry to touch not damp.

Thanks,
Robbo

It's probably from intermittent wetness such as rain. You should be able to kill them with bleach. Without blocking the incoming water from the source, the problem will just come back.

Look at the roof or gutter above for leaks. Or possibly a tank or pipe in the loft.

They are not stains. They are mould. No stain blocker will prevent mould.

Stains will not penetrate from under a decent shellac or oil based stain blocker, if the walls were wet under the paint, it would cause the paint/blocker to blister or crack.

Corners are more prone to stains because the air circulating the room doesn't reach in to the corners. I don't think the problem is necessarily down to damp from outside. If your walls are cold, you will get condensation on them. An external wall in a cupboard has little in the way of airflow.

Bleaching them on a regular basis is the cheapest option. Air bricks and foam backed plasterboard will do the job but cost more. Leaving the doors open slightly will help. Sorry, probably not the advice you wanted to hear/read.