Lime Plaster - Not Gypsum Multi Finish?

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Cockney1

Well-Known Member
not sure why it happens! Could it be that yesterday was very hot? 26 degrees? I properly pva’ed it and waited until it went tacky, by the time I plasteted that section of the wall the pva would have dried, could that be it?

edit: they little crack marks feel completely smooth, they arent actual cracks they just look like it..
You my friend have experienced what we call in the plastering world as “crazing“. You have not controlled the suction properly!
 
You my friend have experienced what we call in the plastering world as “crazing“. You have not controlled the suction properly!
Quick google suggests painting should be alright over this. Its not cracked so hopefully it stays on the wall.

Next time stronger pva then!
 

Cockney1

Well-Known Member
Quick google suggests painting should be alright over this. Its not cracked so hopefully it stays on the wall.

Next time stronger pva then!
Read back to the second line of my words of wisdom to you friend!
Unfortunately for you, My advice don’t come for free so that’s all you’re getting for today. :tanguero:
 

ChrispyUK

Well-Known Member
Try a couple of thin coats of pva first to help prime the walls before putting it on thicker. Usually by the time you've got to the end of the wall, you can go back and put the 2nd on, then when thats soaked in, go on with a thicker PVA mix.

If you've got the suction controlled about right, you should not need much water to finish. Your photos look like you've had to scrape the life out of it.

I'd still get rid of the coving if you have it in other rooms.
 
Thanks a lot guys (not andy :p)

yeah, all getting used to it. Its weird, some walls ive had no issues with, others are absolute bastards! I definitely havent mastered the art of pva’ing yet.

Ill try getting the wall wetter with a few diluted pva mixes before the thicker mix.

i will be taking to coving off the next room for sure. The hall looks awful haha! Thanks again for the help, i go again soon!
 

ChrispyUK

Well-Known Member
Thanks a lot guys (not andy :p)

yeah, all getting used to it. Its weird, some walls ive had no issues with, others are absolute bastards! I definitely havent mastered the art of pva’ing yet.

Ill try getting the wall wetter with a few diluted pva mixes before the thicker mix.

i will be taking to coving off the next room for sure. The hall looks awful haha! Thanks again for the help, i go again soon!
You picked one the most awkward places to start imo.
 
Ive spent all day reading posts / watching vids to get my head around this suction stuff. I wonder if part of my problem is the PVA im using. I wanted unibond but cant find any in this crisis.. i went for an amazon one - Everbuild CONPVA5 Contractors PVA 5Kg https://www.amazon.co.uk/dp/B0012MPV6S/ref=cm_sw_r_cp_api_i_dKnLEb5CBJC99

Ive been doing 1:5 / 1:3-4 (no way of measuring so I eyeball it) before plastering. People on the amazon page suggest using 1:2.. maybe thats why my PVA is drying too fast and gone before I plaster.

Ill try doing a 1:5 day before, few 1:3s before and make the last one the thicker end of 1:3.Nice test to do this week - ill send photos if it stays on the wall.
 
Look up Baumit dg27
I've just ordered better PVA - some Unibond stuff.. wish I'd seen this first. I'll try wetting the wall better next time and getting a few more diluted PVA mixes before I apply the plaster.

I did a bit of a test on the last wall and I did a 1:3 mix day before, then another 1:3 mix before I plastered. That dried quick, so applied more like a 1:2 mix after that and that section of wall worked a lot better. Think I'm going to just try and get the wall as wet as possible and then go for it.

Just need to figure out how to fix the mess I've already made haha
 

superspread

Well-Known Member
Update
Spent two days stripping paper (woodchip on ceilings is a bugger).
today plastered two walls and a ceiling.

ceiling was terrible, too hot and wasnt used to working upwards. Plaster went everywhere and i hated it. The loft hatch + leaning over the banister had me swearing every 5 mins so probably going to have to redo it..

wall went better and happy with that. A few times my plaster wanted to pop (it would break open and id need to wet it down again).. not huge and only a few spots but like it was cracking.

I gave it good pva (1:5 day before, 1:3 before platering) and still had the issue.. any advice?

taking on the big wall tomorrow and going to do it in two goes as its too big to do in one..
Tbh that’s probably a better finish than half the plasterers on here :coffe:
 
Another wall done and dry! I plastered it first with the skirting then decided to take it off so had to fill the bottom.. think it went alright. All the marks make it look pretty poor but its smooth and was a rough lime wall.
 

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I think the damage has already been done majority of the time your problems will start down stairs on external walls. If the backing is lime and it’s just a gypsum skim on top it’s not the end of the world but I think you will get a mould issue in the near future or the paint will flake
 

Wayners

Well-Known Member
You can paint lime plaster with contract emulsion. On old places companies use products like Little Greenes distemper paint. That's as far as my knowledge goes
 
I think the damage has already been done majority of the time your problems will start down stairs on external walls. If the backing is lime and it’s just a gypsum skim on top it’s not the end of the world but I think you will get a mould issue in the near future or the paint will flake
Yeah, to be honest, I've had all the downstairs done by a professional plasterer and they used multi. That was a year ago and no issues yet. I'm plastering upstairs now so hopefully no problems.

The worry is moisture cant escape, but with lime walls and lime mortar I've been told it will escape externally, no need to have both sides of the walls breathing - although that is obviously ideal.

Building Control prefer gypsum plaster to lime because it meets building regs - but they dont differentiate between traditional and modern houses. Historic England also suggest gypsum to a Grade 2 opposite with the same construction and they've not has any issues in 15 years so I think we will be okay...
 

ChrispyUK

Well-Known Member
and my understanding is that its nothing to do with lime vs modern but to do with energy efficiency. Ill find the reference later.
I think the usual rule of thumb is the 50% rule. Anymore than 50% hacked off then they want insulation upgrade. If you’re at that stage then you may as well insulate regardless as it makes a massive difference.
 

Brimstone

Well-Known Member
didnt say it doesnt meet BR. I said they prefer BG.
"Building Control prefer gypsum plaster to lime because it meets building regs " i.e. lime doesn't meet Building Regs. Insulation is not the issue with either material, but I suspect Building Control are not correct or are getting the two issues mixed up.
 
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