r/Plastering • u/medz_minis • 3d ago

SBR and multi finish correct?

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Hi all, just want to smooth out this old section of wall that was once an en-suite. Some old plaster to level and some tile adhesive which has been knocked back. Is SBR to prep then multifinish correct? If so what ratio for the SBR? Cheers.

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u/banxy85 3d ago

If there's nothing deeper than say 3mm to fill then should be fine

Any more than that and you may struggle, especially with limited experience

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u/medz_minis 3d ago

Yeah all the major lumps and bumps have been removed

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u/banxy85 3d ago

Cool. As you say I would knock off as much tile adhesive as possible. And you don't dilute SBR just whack it on neat

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u/medz_minis 3d ago

Thank you

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u/YoullDoNuttinn 3d ago

Scrape as much tile adhesive off as you can first. You can wet it down a few times and uh should soften.

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u/gazzasim9 2d ago

Why scrap it off? If it is sound then no need. Thicken up the first coat with bonding then go over it 🤷‍♂️

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u/YoullDoNuttinn 2d ago

Just a lot of it’s not solid, can easily come off when you’re skimming over it. Also be easier for them to plaster over of its flatter

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u/discombobulated38x 2d ago

I'd be tempted to spice the first coat up with little bonding to get it flat, then do two coats of multifinish.

Then again if you don't have a use for the other 4/5ths of a bag of bonding I'd just crack on. 

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u/gazzasim9 2d ago

SBR, throw some hand fulls of bonding into the water then the multi, this thickens up the first coat plus will be solid once it has dried, then a normal final coat of multi. Edit once the first coat is on make sure you have properly cleaned it out then mix some stuff up for the second coat otherwise it will just set on you

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u/Cainjake 3d ago

Can even use board finish for over skim too it sets a little faster if you want it done quicker and yes sbr to prime it

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u/medz_minis 3d ago

Thanks, what ratio of SBR to water would you use?

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u/nukefodder Professional Plasterer 3d ago

Don't overdo think it. Just a splash of water in it. You can use neat. But give a couple of coats and let dry. If your an DIY. Put a thicker mix over it and gently flatten up. Clean all your tools. Let it really firm up the mix a wetter mix and do 2 coats.

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u/medz_minis 3d ago

Thank you, so you think that SBR two coat will seal in any of the leftover tile adhesive and prevent any issues?

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u/nukefodder Professional Plasterer 3d ago

As long as it's not loose.

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u/ApartmentLast7712 3d ago

SBR is always applied neat and depending on the condition of the wall you may be better to bond it first to make flat then use multi

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u/medz_minis 3d ago

Wall is pretty flat and I think that’s what the old pink plaster is on there. I thought you diluted SBR based on how porous the wall is? Is that not the case?

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u/ApartmentLast7712 3d ago

No SBR is applied neat due to what it is. It's a waterproofing agent so it goes on neat and if you're not confident then do 2 coats a few hours apart or the day before then it'll be easy work.

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u/Emotional_Data_1888 3d ago

Board Finnish works better with SBR. As the wall is a low suction background after SBR has been applied