How to plaster wall after using cement concrete masonry waterproofing?

[DIY_Duncan]

Hi there, after scraping off bubbling paint and plaster and after applying Bondall Silasec Cement Concrete Masonry Waterproofing I intend to then plaster over before painting a relatively small area of wall. I am looking for advice on the best plastering solution to use. Thanks.

  

[Dave-1]

Afternpoon @DIY_Duncan 

Welcom to the Bunnings community page There are lots of interesting questions in here with answers Your looks like an interesting question for sure.

Have you scrapped away more of the paint/plaster since the photo? Whichever way forward the flaky parts need to be removed. If you try and smooth the edge then the original issue will return for sure.

Do you have water running down the outside of the building is the next question? I am just wondering what the reason the paint bubbled in the first place. I have a sneaking suspission that the area that you will need to waterproof is larger then the area you have stripped back. 

I havnt put plaster direct on a wall before so had a squiz on dr google. Sounds like two or three stages will be needed. I would suggest to wait for @MitchellMc  or @EricL as they will be a lot more knowledgeable.

Dave

[DIY_Duncan]

Thanks, Dave. I have scrapped off what comes off easily enough for now and don't intend to take it too much further. There's no running water down the outside of the building but this corner doesn't get much sun. I've checked and there's no other bubbling - phew! I also now have a ceiling fan for circulation and keep things open on warms days. 

So next it will be onto plastering. All new to me and unsure of the best type of product. Thanks, again.    

[EricL]

Hello @DIY_Duncan 

Welcome to the Bunnings Workshop community. It's marvellous to have you join us, and thanks for sharing your question about plastering your wall.

Normally I would suggest using Dunlop 16kg Ready To Go Premix Render. But because you've used a waterproofing compound on top of the concrete, I'm going to have to make some inquiries regarding compatibility. Let me call our supplier tomorrow and as soon as I have more information, I'll get back to you.

Thank you for your patience.

Eric

[DIY_Duncan]

Thank you, Eric. I haven't yet applied the waterproofing compound if that helps. Cheers, Di

[EricL]

Hi @DIY_Duncan 

I'm just waiting on a reply from our supplier regarding the compatibility of the render to the water proofing membrane. Should you decide not to use the waterproofing agent you can render the wall directly with the Dunlop 16kg Ready To Go Premix Render.

Please make sure to wear personal protection such as gloves, goggles and mask when working on your project.

Eric

[DIY_Duncan]

Thank you, Eric. I too have called and it's not going to work with the Bondall cement concrete masonry waterproofing. So, I am now after a solution without using the cement concrete masonry waterproofing. I would still like to waterproof but will need to also plaster/render it before painting. Are you able to recommend a solution? Cheers, Di 

[EricL]

Hello @DIY_Duncan 

I've just been in contact with Dunlop, and they've suggested using Dunlop 20kg Fine Coat Render first to create the fine finish for your wall. In regards to the moisture barrier, they recommend using Dunlop 4L Damp-Proof Waterproofing on top of the render. The technical team at Dunlop have recommend applying two thin coats rather than putting on a very thick coat.

Once the moisture barrier cures you can then paint it with your choice of paint primer and topcoat. My best advice is to give the fine coat render enough time to cure before applying the moisture barrier.

Please remember to wear personal protection such as gloves, goggles and a mask when working on your project.

If you need further assistance, please let us know.

Eric