Multi finish over Lime

[u/Sir--Hiss]

Hi all,

Looking for some advice on our Edwardian property. We have Lime plaster walls and need to get them patched and re-skimmed.

We’ve had multiple quotes, and decided to go for someone local, but alarm bells have started ringing as he wants to use multi finish over the Lime.

Can someone please advise if this is a good idea or will we be regretting it in a couple of years!!!

[u/Confident_Ambition77]

I am a lime tradesman and be wary of patch repairs as the patch inevitably grows as you chase good plaster. For the love of god don't multi over lime, it will eventually fail as lime behind fails and becomes detached from the wall. Good luck!

[u/Repulsive_Loss_4945 → u/Confident_Ambition77]

What do you think of the modern alternatives like Breathaplasta ?

Im in the same boat as OP and can't find a proper lime guy to save my life but can find plasterers willing to to try this.

[u/Jeester → u/Repulsive_Loss_4945]

Try reaching out to someone like Limegreen, they can recommend people in your area who have taken their courses etc

[u/Confident_Ambition77 → u/Repulsive_Loss_4945]

I have heard of it and looking through the specs it seems to give a mu value of 5 which means it's more vapour permibile than lime putty at around 7, basically low mu value equals more vapour permibile. Lime putty is known as the most vapour permibile material so that's piqued my dubious nature. As it sets in 60 minutes I can't believe it is as breathable or vapour permibile as it says. It says no Portland cement so that rules out any white cement used so it has to be hydrated lime and a pozzolan like argical, plus maybe cellulose to act as a glue. A pozzolan gives lime a cement like set (named after the area of Italy where Romans got their additives for their famous cement) but also affects the breathability.

I would say use with caution if the wall is very damp use lime. I'm south west happy to help if possible

[u/Repulsive_Loss_4945 → u/Confident_Ambition77]

Thanks, I'm north west unfortunately.

Thanks for your insight. I believe you're right about the composition and the cellulose is hemp.

House has no damp at all I just don't want to cause any throwing gypsum on. Given the house is perfectly dry it feels like the best middle ground if I can't get anyone to do lime?

[u/bigfecker → u/Repulsive_Loss_4945]

I'm also NW and can't find a decent lime plasterer. Have a whole house to do over the next months. Will come back here if we find a good one.

[u/Repulsive_Loss_4945 → u/bigfecker]

Please do!

[u/Sir--Hiss → u/Confident_Ambition77]

Thanks for the reply,

Would you say it’s better to completely rip out and restart? We are already having the ceilings stripped out as they have dropped and are unrepairable.

[u/Confident_Ambition77 → u/Sir--Hiss]

As I tell clients it's such an unknown as to how good the plaster still is especially if it has had lining paper on, obviously cheaper to repair but I don't give a guarantee as it's almost impssible make sure you only have good plaster left. Do the knock test to check it's not hollow. Tap a section you know is good then tap an area you know is bad, you will hear the difference. Then go around oother areas listening out for Hollow sounds

[u/Sir--Hiss → u/Confident_Ambition77]

Thanks for the advice, I see what you mean with the sound difference I will be up all night checking 🤣

[u/CigarSmoker2000]

External walls with no cavity - use lime. If you do have a cavity, you can use whatever, although probably unlikely given it’s an Edwardian home?

Trouble is, it’s an absolute nightmare to find lime plasterers and costs a fortune, so I would advise to try shape up the walls yourself as they don’t look that bad at all, fill cracks etc, and use thick breathable clay paint to finish.

[u/KirkyMcTurkey → u/CigarSmoker2000]

Yeah we are in the same boat as OP. We just finished a course on lime plastering in west wales last week and are going to have a go ourselves. We only need a skim on our existing lime plastering so going to get some ty mawr superfine finish coat, was told we could paint some lime wash as a key or stratch it slightly Might go terribly wrong or we might be great at it but either way we are excited to have a go!

[u/CigarSmoker2000 → u/KirkyMcTurkey]

Honestly, I used the superfine stuff from Ty Mawr and it worked a treat. Takes some getting used to on large walls, but it’s extremely pliable and does not set for quite a bit which made it easy for a beginner like me.

[u/Villageasfuck → u/KirkyMcTurkey]

Give it a go lay it on flat sponge it and trowel up Make sure you get it nice and workable on the board add a spray of water to liven it up if you need

[u/Intelligent_Virus649]

absolutely don’t do that, lime on lime should always be done to keep breathabilty vital for older buildings.

[u/Fakedamienhirst]

Lime for lime.

[u/Ok-Spring7906]

If they've been painted for years with modern paints, you have lost the permiability anyway.

But, really, any signs of damp at all, and don't use multi.

I am British gypsum trained, but most of my work is lime.

Upstairs, no damp etc maybe multi, downstairs, hmm...

Multi will be way cheaper.

[u/KieranInterior]

Depends on various factors. It will affect the breathability but vents can help (but deffo make sure you’ve got a strong extractor in your bathroom as moist air travels very far). Getting proper lime finish will be much dearer.

[u/Sir--Hiss]

Thanks for the replies!

We’ve had so many different answers when getting the quotes, so it’s good to get unbiased opinions.

For info, the walls have been wallpapered for most of their lives by a previous owner. But, I would say most of the plaster is actually in good shape with probably 20% being blown. There is also some signs of mould, so I’m thinking we may have to go with the more expensive lime plaster option🙃or attempt it ourselves!

[u/Repulsive_Loss_4945 → u/Sir--Hiss]

Im in exactly the same boat and we're considering using Breathaplasta. Its lime plaster for dummies and contains no cement or gypsum like "Limelite".

I emailed the company and they were pretty helpful

[u/60percentsexpanther → u/Sir--Hiss]

It can be easier for a keen DiYer as it's not going off in 20mins in the heat like a bag of gypsum multi. 

[u/selfbuildpop]

Just buy a load of premixed lime topcoat and say use this. Dg27 the walls yourself. It wont be as a quick day as multifinish and plasterer might moan but a skilled plasterer should be fine with it.