removing paint from lime plaster

[skier-hughes]

As I move to finishing the cleaning of the beams, I need to remove the modern paint from my lime plaster.

You can see what I have to do here
http://www.myvideoproblems.com/testfiles/personal/kitchen/26-09-07_1709.jpg

Now some or even most of the lime plaster is very delicately balanced as to whether it stays up up falls down, any major work on it will certainly be disasterous, so whatever I do, if I want to retain as much of this lime plastering as I can, needs to be done with great care.

I certainly can't put kling strip on and blast with the vacwash :shock:

I have emailed Strippers for advice, but following on from another post this morning, many people seem to have done this already, so I thought I'd start another post rather than tag on to crazing lime plaster.

There isn't a great deal of paint coverage, maybe a couple of coats and it appears to be emulsion.

Graham

 

[Ian Bond]

I've just done the ceiling and walls of bedroom, but it was tedious work and took a couple of weeks. Probably because I kept finding other less tedious jobs to do in between!

I lost very little of the original plaster, only some small patches that were very loose and falling off. Obviously extreme caution is needed if your plaster is fragile, there are ways to consilidate it. I've used stainless steel washers to secure plaster to laths.

I used a sharp scraper only on the ceiling, which had been coated in Evenceil by me in ignorance many years ago. Suitable penance I think. This was much easier to remove than the old emulsion on the walls for some reason.

I used a hot air gun (probably not a good idea, see later) and scraper to remove the bulk of the emulsion from the walls. Try not to burn the paint, just soften it enough so it begins to blister and can be scraped.

I then used a steam stripper (hose only, plate removed) and the scraper to get as much of the remaining paint as possible off (wear suitable rubber gauntlets to avoid accidental scalding, H&S would not approve of my technique).

The steam approach worked much better than the hot air gun, so I could have just used steam from the start. The paint just would not budge in some areas, as if it had soaked in. Could be my heatgun made it worse, so be warned.

Steam and water really do loosen the paint, and I managed to get 95% of the paint off this way. But it took at lot of scraping and tested my patience to the limit, and beyond :/

I ended up with just small flecks of emulsion in the pits and cracks of the wall.

Finally I washed the wall down with water, decorators sponges and those green pan scourers, being careful not to damage the plaster. This got more of the stubborn bits of paint off, and got the lime plaster clean.

The room looks much better now I've repaired the plaster (with lime of course). You'd never know it had been pink (not my doing) and yellow (guilty, the tin said it was Straw Boater or something, hmmmm).

Now for the limewash. Thankfully there's not much emulsion elsewhere, as layers of wallpaper had protected the limeplaster from 'progress'.

btw - the steam technique helped remove the stubborn bits of gypsum skim that hadn't cracked and fallen off with very little help from me.

Good luck!

 

[Ian Bond]

I'm sure you be very careful Graham, and try out any paint removal technique on a small area, stopping if it looks like causing damage. The low pressure steam and careful scraping worked OK for me, but would have to be used with extreme caution....

Just to add to the fragile plaster bit, people have different ideas about
what's savable.

I try and save as much as possible: stainless washers to repair lath and plaster, dilute lime putty to consolidate lime plaster on solid substrates.

There are hollow sounding patches of plaster on my walls that are adequately held on by the surrounding plaster, and only slightly cracked. Some people would condemn this and rip it off.

A neighbour showed me his replastered walls (gypsum) explaining that the old lime was shot. He demonstrated this by removing a chunk of remaining 'blown' lime plaster, prising it off the wall with some effort. Aaaaargh.

 

[skier-hughes]

Some of the plaster is still whole, but it is very moveable (?) if you push it in the whole section moves in and out.
I think it is worth leaving in.

Some is nice and firm.

Some is starting to fall apart, so repair here is neccessary.

Some is gypsum on laths, and will come out carefully. Luckily whoever did it wasn't the worlds best plasterer, so gentle persuassion is enough and so far I've not damaged any laths.

Graham

 

[Ian Bond]

The laths used in my house vary considerably in strength - some are extremely thin and flexible, with much more solid neighbours.

I've been luck in some areas and managed to wriggle chunks of gypsum out without breaking laths, but other areas were so solid I left them alone and plastered around them.

Flexible is good - that seems to be the stuff that survives the longest.

If you can't get behind the laths to make repairs, you may be able to use repair washers. I've had mixed results with this, but have managed to save more than I lost. Sometimes, after removing a washer sized area of the setting coat, the plaster beneath has crumbled to dust leaving bare laths. In other areas, the scratch coats were still intact and flexble enough to fix back through the lath, ideally to a joist/stud. I have managed to fix washers into just the lath, but this is trickier - don't want to split it, or deform it so that the plaster nibs get damaged. I drill pilot holes, and always drive the screw in by hand - not with a power driver, so I can be gentle as possible with it.

This is probably not an approved conservation technique, but where I suspect the plaster is very weak I put the washer over the whole lot, finish coat and all. I've then stuck a piece of fibreglass mesh over the washer, and skimmed over the repair.

 

[Ian Bond]

Here's an example of a repair I did to the attic walls:

Two layers of plasterboard removed, loose plaster refixed with stainless steel washers and screws:

Modern emulsion stripped (using Klingstrip on this one, not steam!)
Washers covered with fibreglass scrim tape, walls part skimmed with fine lime plaster.

Although the walls were bady damaged by years of bodging and neglect, I managed to save about 50% of the plaster (that was one of the better sections). Not perfect, but at least some of the original craftsmanship survives for the future.

 

[Nemesis]

Well done!

We are about to embark on our staircase, which has loose lime (200 plus years) and some gypsum bodge also.

Should be fun.

 

[Ian Bond]

Is it rendered direct to the masonry or on laths Nemesis? Good luck with it, hopefully the gypsum's just small patches. It's great when the mess had been cleared up, and you set to work on the repair. I gave up dusting years ago - no point moving it about the place.

I've had to resort to the chisel on an SDS hammer drill to get the most stubborn gysum plaster of stone before, but perhaps judicious use of water would have made it easier to pry off by hand? My neighbours would prefer it - have to be considerate in a terrace!

 

[Lime]

Each wall/ceiling is different and scraping off old paint will always be tedious.
However, regardless of the various methods used above, the most important aspect is to have a sharp scraper.
A Stanley blade scraper works well on most surfaces and on a typical ceiling 14'x14' I'd consume perhaps 30-40 blades.
QD do 5 blades for a few pence so don't spend a fortune.

 

[Nemesis]

Ours is a bit of both Ian - don't think there will be a problem removing it. and no neighbours, but there's a fair bit loose from the laths and some crumbly patches which I think are beyond recovery.

We shall see.

Bottom coat of paint is a rather good Geo pea green, walls very wobbly indeed!

 

[Ian Bond]

Wobbly lime plaster - so much nicer than skim on plasterboard.

Hope you can post a pic if time allows, the paint sounds interesting...

 

[Nemesis]

The top is nasty dark green!

 

[Ian Bond]

A Stanley blade scraper works well on most surfaces and on a typical ceiling 14'x14' I'd consume perhaps 30-40 blades.

You should be in the circus with an act like that, Lime

.... I'll get me coat.

 

[Nemesis]

:lol:

 

[Lime]

:lol: :lol: :lol:

 

[Ian Bond]

Graham

Using Klingstrip on those walls of yours would probably be the safest (and most expensive) way to get that paint off.

I used Klingstrip to pull the paint of a fragile attic ceiling, and it worked well - it practically removed itself by falling off in sheets.

However I did not blast the stuff off with a vacwash, just gentle scraping followed by bucket and sponge.

Perhaps klingstrip for the more fragile areas? Just thinking that steam may be too harsh for very weak plaster.

Anyway, hope it goes OK and looking forward to seeing the pics of the finished job. The ones where if you've done it right it looks as though you haven't actually done anything (without the 'before' photos for comparison).

 

[skier-hughes]

Some work has got in the way at the moment, plus some other items that need doing first, so I'll report back when I've got a bit further.

Graham