How to render over painted block walls?

[AD2025]

I have a home built in the mid 70's. The internal walls of the bedrooms are painted concrete block. I want to render/plaster over the blockwork which is quite straight. The walls have not been painted in about 20 years. Some of the paint is flaking off. The last coat of paint was water based. What preparation must be done to the block work for render/plaster and what product should be used?

I am also looking at installing 90mm cornice and the preparation should allow for the cornice cement to adhere. 

Also, do Bunnings provide trades people who can provide any of these services?

I have attached some photos for reference and information.

Thanks for your time and response(s) in advance.

AD

[EricL]

Hello @AD2025 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about rendering your painted block walls.

It is possible to strip the paint of your wall using either a chemical paint stripper or a mechanical stripper such as wire cup. Both of these will generate a great deal of mess and debris so please make sure to wear personal protection such as gloves, goggles and a mask. Once all the loose paint has been stripped and the wall cleaned properly you can then begin to render the surface.

However, another option would be to cover your wall with Gyprock plasterboard. Aside from the convenience it will not generate as much debris and covering the wall will be much faster. Here is a link to the Gyprock installation manual.

Here is a handy step-by-step guide: How to use Gyprock Plasterboard to cover a Masonry Wall 

In regards to installing cornice, it can be fixed into place using small fixing nails and adhesive. I'm sorry but Bunnings does not provide this type of installation service. I propose putting the job on either Airtasker or Hipages.

If you need further assistance, please let me know.

Eric

[AD2025]

Thanks for the information Eric

My preference is to not use gyprock and to render/plaster over the concrete block walls. What products do you recommend for this?

I look forward to hearing from you.

[MitchellMc]

Hi @AD2025,

If you were to go to the effort of removing the paint from the wall, which will be a tedious and difficult process, you could then use Dunlop 20kg Multipurpose Acrylic Render. 

I also want to point out that using plasterboard will be exceptionally easier, require far less preparation, be done within a couple of days rather than a week and cost significantly less than rendering/plastering the walls. I understand you have your reasoning for not wanting to use the boards, I just want to make sure you're aware of the additional cost and times that will go into it.

Please let me know if you have any questions.

Mitchell