Choosing filler for rendered basement wall/lightweight concrete?

[Jomp3]

We want to make our newly built basement rooms more cozy and have therefore planned to plaster the rendered walls for a completely smooth finish. The walls are made of lightweight concrete blocks that are base-rendered and then finely rendered with plaster mortar C.

Which filler should be used? How should I pretreat?

The walls are intended to be painted afterward and we would like to future-proof and make everything as moisture-resistant as possible in case of unexpected flooding.

 

[philsson87]

I see that you didn't get any response. I have the same question. What did you do afterwards?

 

[Stefan N]

No filler at all and paint with lime paint.

 

[Jomp3]

I see that you didn't get any response. I have the same question. What did you do then?

Primed with a breathable acrylic primer like deep primer, then regular roll putty and painter's putty, used the same paint as on the other floors after consulting with the paint store. Turned out very well!

 

[philsson87]

Primed with an acrylic primer that breathes like deep primer, then regular roller filler and painter's filler, used the same paint as on the other floors after consultation with the paint store. Turned out very well!

Nice! Thanks for the answer and the tip. You didn't have anything you needed to repair on the walls, like from plugs or other damage, or previously painted surfaces? How did you handle that if so? I have a mix of plaster, bare and repainted with a couple of different colors, and holes I need to fill in. One reason for this is that I've knocked down some walls and combined 3 rooms.

EDIT: I clearly see in your picture when I look back at it that there is missing plaster at the end of the "wall" there. How did you fill this in, did you use filler?

 

[Jomp3]

Nice! Thanks for the reply and the tip. Did you have anything you needed to repair on the walls, like plug holes or other damage, or previously painted surfaces? If so, how did you do it? I have a mix of plaster, bare and over-painted with a couple of different colors, and holes I need to fill in. One reason for this is that I've knocked down some walls and combined 3 rooms.

EDIT: I can clearly see in your picture when I look back at it that there's a lack of plaster at the end of the "wall" there. How did you fill this in, did you do it with filler?

The image is of a doorway where there is a frame today, see the after-image. We have expanded with both old and new basement walls that have been replastered. I've repaired old aerated concrete walls with a filler mortar like Finja laga vägg.

The solution with regular filler is not moisture-resistant, so I had to abandon the idea of making the surfaces in the bedroom flood-proof. However, we have painted all storage and technical spaces with KC-paint.

 

[philsson87]

The image is of a door opening where there is currently a frame, see the after-picture. We have extended with both old and new basement walls that have been plastered. I have repaired old aerated concrete walls with a filler mortar like Finja repair wall.

The solution with regular filler doesn't become moisture-resistant, so I had to abandon the idea of making the surfaces in the bedroom flood-proof. However, we have painted all storage and technical spaces with KC-paint.

Well done! You didn't consider cement-based filler (maybe this is even though it's not explicitly stated in the product sheet), I thought it might withstand water better. In the datasheet, Finja's wall filler seems to suit my needs quite well with its adhesion ability on, among other things, paint (with the right primer) and that it can be tiled on. I started a thread for my question as I would like some more input, but thank you very much for your help. You always learn something!

My thread
https://www.byggahus.se/forum/threads/laga-spackla-mala-putsvaeggar-enhetligt.557529/

 

[Jomp3]

Well done! You didn't consider cement-based filler (maybe this is even though it's not explicitly stated in the product sheet), thinking it might withstand water better. In the data sheet, Finja's wall filler seems to fit my needs quite well with adhesion ability on, among other things, paint (with the right primer) and that it can be tiled on. I started a thread for my question as I wanted some more input, but thank you very much for your help. You always learn something!

My thread
[link]

Cement filler is difficult to sand effectively, so to get a smooth result faster, this solution was chosen. Good luck!