Removing paint from lathe plaster?
December 22, 2003 9:07 AM   Subscribe

I have an old house with lathe plaster. There are rooms that have had peeling paint that just got painted over a few times in the distant past. I do not much like the way it looks, and I would like to expose the bare plaster and start fresh. Is there any way to remove all this paint? I do not want to sand the ceilings of such large rooms, as I feel I will get tired of that real easy. I have not seen any solvent that lists paint on plaster as an appropriate use. I am quite confident that the plaster itself is sound and uncracked. Help me Obi Wan Kenobi, you are my only hope.
posted by thirteen to Home & Garden (15 answers total)
Get a heat gun, scraping tools and a respirator.

It takes a while, but is less time consuming and less messy than sanding.

The respirator should be one that filters VOCs and other gaseous nasties - heating paint to that temparature causes outgassing.
posted by tomierna at 9:26 AM on December 22, 2003

My mother spent many years buying abandoned antique homes, refurbishing them, and reselling them. Here is her trick.

She long ago abandoned the idea of stripping paint off plaster walls ... too messy, to smelly, and generally the plaster is too unstable to survive the process. This is especially true in pre-1865 homes, where the mix of the ingredients in the plaster can be very iffy.

Instead, she'll sand the walls (by hand, actually, not with a power sander -- using as heavy a grit sandpaper as she can) in the spots where the pant is actually peeling. The goal is to remove the loose paint while leaving that paint which is 'well-stuck' in place.

The she uses joint compound (the stuff you use to plaster sheets of drywall together, easily findable in any DIY store in huge buckets) and smoothes a very thin layer of the joint compound over (at minimum) the places where's she's sanded the paint off ... more often over the entire wall surface. In essence, she is "replastering" the wall. The joint compound will seal in the old paint and is sturdy enough to (generally) keep any future paint loosening to a minimum. Then sand again (fine grit, this time) and you're ready to paint.

I know it sounds like a time consuming process, and it does take a bit to learn how to use the tools to spread the joint compound in a thin smooth layer (but the nice folks at the DIY store will certainly help you with this), but it isn't nearly as bad as trying to strip paint off plaster. She and I recently did a 14 x 14 bedroom in my house (strip wallpaper, sand off paint, joint compound, let dry, sand) in a weekend (Friday night - Sunday).

And get a good respirator. Breathing in all that dust (not to mention paint fumes) will make you sick after a while.
posted by anastasiav at 9:32 AM on December 22, 2003

Heat seems the best. Perhaps this stuff might work.
posted by clavdivs at 10:03 AM on December 22, 2003

Don't forget that you might be sanding lead-based paint.
posted by turbodog at 11:13 AM on December 22, 2003

Ditto on the sand, mud, repaint system of anastasiav's mom. I've used it on a couple lathe-and-plaster walls. Old plaster is not very mechanically stable. Heat and scrape is very hard on the wall. The less you do to it, the better. Also, you want to minimize oil paint chipping to reduce your lead exposure.

How ever you do this, wear a proper respirator and eye protection. Those pressed-felt or lint "masks" offer no protection at all. If you opt to use heat, buy the VOC/paint/solvent/organic vapours filter. If you sand, buy a HEPA (PM10) filter. Don't minimize the effect chemicals and particulates can have on your health.
posted by bonehead at 11:24 AM on December 22, 2003

I thank you all very much, this is the kind of information I wanted.

I definitely have lead paint according to a testing kit I got at the hardware store. Local laws have changed regarding the disposal of lead paint, as they do not want to place barriers to removal of hazardous substances. I want to do this in a responsible way, but I also need to be somewhat speedy as well. I like what I am reading.

I also have wood floors I am planning on getting lightly repaired. Would it be wise to do that before or after the walls?
posted by thirteen at 11:28 AM on December 22, 2003

After. Absolutely after.
posted by anastasiav at 11:32 AM on December 22, 2003

An additional word on scraping from any surface: pull-scrapers are vastly superior to push-scrapers, whether you're scraping dry paint chips or working with a heat gun.

It seems like a putty knife and some muscle is the way to remove peeling paint, but that's a sure recipe for gouges. Instead get a pull-scraper and keep a whetstone handy to keep it sharp. It seems like a trivial distinction, but what you want to do is shave the paint off, not dig it up.
posted by salt at 12:08 PM on December 22, 2003

I agree with the other techniques given here — my experience was on a house from the 1930s, and had a mix of stable plaster and some which was simply turning to powder.

In the cases where it was sturdy, I’d use the heat gun, and in the cases where it was buckling or otherwise deteriorating, I'd usually rip it and the lathe out and patch with drywall.

Two things made these techniques easier for me:
1) The lathe plus the plaster was just a little thicker than 1/2 inch drywall
2) All of the walls and ceilings in the house were textured with a pretty-simple-to-learn hand texture technique which I was able to duplicate with drywall mud.

Oh, and what anastasiav says is absolutely true about the floors. Finish everything else and do the floors dead last.

Good luck!
posted by tomierna at 12:13 PM on December 22, 2003

I also have wood floors I am planning on getting lightly repaired. Would it be wise to do that before or after the walls?

After. Absolutely after.

Finish everything else and do the floors dead last.

I respectfully disagree, based on sad experience. If you are planning on having your floors sanded, you should absolutely do them before the walls. The grit and dust from the sanded floors will make a hideous mess of your newly replastered walls, I can all but guarantee it. It means you'll have to be more careful drop-clothing your floors when you paint, but it's worth it to avoid having to damage your walls trying to get all that dust off...
posted by JollyWanker at 2:05 PM on December 22, 2003

JollyWanker, I'm sorry to hear of your sad experience. But, I have to ask, how long did you wait between the plastering and the floors? We generally wait about two weeks to a month between finishing the walls and moving to the floors, and we've never, ever had a problem like that.... even after doing at least three dozen rooms.
posted by anastasiav at 2:17 PM on December 22, 2003

Of the six rooms in the house I did, we did all of the ceilings and walls first.

Simply make sure your plaster and paint are cured before working on the floors, and then after you're done with the floors, wipe down the walls with tackcloth or wash them with a mild detergent.

Also make sure the sanding tools you use have vacuum-assisted dust collection.

The main reason to do the ceilings and floors first is because when you are doing plaster demolition, you can never be sure that the stuff will fall where you want it to.

Falling plaster puts gouges in your polyurethane, even if you have several layers of dropcloths down.

Oh, and speaking of falling plaster gouging things, wear tough work clothes when you're demolishing plaster ceilings, especially if they are plaster over metal lathe (common in heat-resistant plaster installations). I have a three inch scar on my leg from where a piece of metal lathe embedded inside a large chunk of plaster raked through my jeans and skin like it was a hot knife through butter.
posted by tomierna at 3:12 PM on December 22, 2003

Rather than doing either walls, floors etc first, I would suggest getting all the major renovation out of the way (re-plastering, major sanding etc) over the entire room, then you can clean the mess up and start on the finishing process without having to worry about making a huge mess on new finishes. Basically aim to prepare all the surfaces to the point where you are ready to start final preparation for painting.
posted by dg at 3:26 PM on December 22, 2003

Lead is serious stuff and removing it is not to be taken lightly. If you have children or are planning to anytime soon you'd be foolish to do it yourself. Any removal method will release lead dust and/or fumes in the air. Children exposed to lead develop permanent impairment. Unborn children develop birth defects. So don't do it yourself with kids around - hire a lead abatement company (very expensive), or paint over with a lead encasement paint, or wallpaper.

If you don't have kids and want to do it yourself you'll still need to take precautions. Use a HEPA face mask. Get a HEPA vacuum to clean up debris. Wear a disposible Tyvek jumpsuit. Work on one room at a time and seal it off from the rest of the dwelling with plastic dropcloths. Don't bring anything from the room you're working on into the living quarters - remove your jumpsuit and shoes before you leave the room.

Having said that, I've worked with lead-painted plaster many times. I agree with anastasiav's recommendation to skim-coat with joint compound. I've had good results by scraping off only very loose paint, cleaning the surface well (TSP), and applying liquid sandpaper, which helps the joint compound stick.
posted by TimeFactor at 7:44 PM on December 22, 2003

TimeFactor beat me to it.

Lead paint is no joke. Look up "Heavy metal poisoning" (lead, mercury, cadmium.....) on Google. You'll see what I mean.

When my wife and I were buying a house, our real estate agent told us a story about a couple who took to removing their lead paint with power sanding, and no masks but those silly "comfort masks" - They were never the same, he said.

We told this story to another real estate agent who quipped : "Well - everybody I knew grew up with lead paint, and we turned out OK". But - of course - OK doesn't equal "The highest expression of neurological and physical potential which is allowed given the possible range allowed by the DNA". It just means "OK", as in "not obviously retarded"

So if you have children.....yikes.

I got lead poisoning from lead paint removal when I was 12 or 13. I think I mostly escaped significant neurological damage - except for some attention-deficit problems - but the transient effects - chronic depression, manic depression, fatigue, persistent yeast infection, and sexual dysfunctions.....blah blah - took 20 years or more to go away.

But there were upsides to the whole mess : my memory is MUCH better than when I was 20, and sex is better too!

Anyhoo.......what about encapsulation? If the plaster is not completely crumbling off the walls, you could just scrape off the loose lead paint - using the heavy duty prophylactic measures such as TimeFactor's HEPA suggestion, for health safety - and then spackle, sand (just the skim coat and NOT the lead paint itself!) and then use a high quality paint. Further, you can deal with woodwork by removing it and having it stripped down to the wood or - if you don't want to do that - scrape it and then encapsulate it with a super hard epoxy based paint.
posted by troutfishing at 3:20 PM on December 23, 2003

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