Primer or not for basement wall

[Makethemsuffer]

Hello!
I have just knocked down all the loose plaster on my basement walls and am scraping off all the old plastic paint (two layers in different colors🙄).

I think I have heard both that you should not prime and that you should prime before new plastering. It is a cast foundation from the mid-30s. I want the wall to let moisture through.

So my question is, should I use a primer before I plaster the walls again? And is it c-bruk I should plaster with?

I also plan to install radiators from my heat pump in the basement after this, will this help with the moisture?

Regards

 

[ansic]

The wall will continue to be able to breathe with primer. If the wall is highly absorbent, primer helps to slow down the absorption, so you don't have to water the wall as much. If there's paint left on the wall, you must use primer there. On clean, dust-free concrete, primer should not be needed.

 

[Sam Petrovich]

Hello,

What effect are you trying to achieve when using primer on the paint? I am working on the same project right now, where I've scraped half of the wall and plan to use primer to bind the plaster to the surface. But the other part is completely fine, and all the old plaster is intact, although it has those bold colors from the 70s that we want to paint over later. What I'm not sure about is whether it's necessary to remove the paint that might not be breathable. Can primer help to open porosity through old paint? And by removal, I mean scraping it off, which might be very unnecessary.

 

[ansic]

Primer ensures that you get adhesion. If it is an exterior wall, I would try to remove as much as possible of the old paint. An interior wall, if the paint is firmly attached, I wouldn't bother removing it.

 

[Plupp 405730]

Hi!
I just knocked off all the loose plaster on my basement walls and am scraping away all the old plastic paint (two layers in different colors🙄).

I think I've heard both that you shouldn't prime and that you should prime before new plastering. It's a cast foundation from the mid-30s. I want the wall to let moisture through.

So my question is, should I use primer before plastering the walls again? And is it c-bruk I should plaster with?

I'm also planning to install radiators from my heat pump in the basement after this; will this help with the moisture?

Best regards

You usually don't prime when plastering with traditional plaster mixes; if the wall is dry, it should be pre-wetted beforehand..

 

[Fjonken]

Saturate the surface with water only, that's sufficient. If you want to prime, use an outdoor primer.

 

[Sam Petrovich]

Primer ensures that you get adhesion. If it's an exterior wall, I would try to remove as much of the old paint as possible. An interior wall where the paint is stuck, I wouldn't bother removing it.

Thank you for your answer. Everything I talked about is on interior walls of the basement. The one retaining paint is because the moisture hasn't penetrated, and the drainage works fairly well on most parts of the house. It's starting to look nice with just c plaster and a skilled hand (not mine but my partner's)