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Discussion Starter · #1 ·
Failed skim coat situation.

I have my own suspicions, but wanted to get some feedback from those with more experience with plaster rather than sheetrock. I have a professional background with sheetrock and painting, but very little with plasterwork.

I live in an apartment (long term renter) with plaster/wood lathe construction. There’s been construction here to repair a collapsed ceiling due to joist failure from water damage (I was not the contractor). During this construction the owner agreed to skim coat several other rooms, which due to the decades of neglect and were not looking so good. This was a mini renovation of sorts.

The contractor doing the skimming is not licensed with my city (though no license required for work not requiring a permit, such as skimming). He had the usual illegals doing the actual work. The workers were very good mud guys at least with regard to their hand skills. However these walls are 80 years old, have numerous old coats of oil paint and also have numerous coats of latex/acrylic paint over the oil. This is par for the course in an apartment like this in NYC where landlords in apartment buildings looking for a quick buck with no money layout use the cheapest paint possible, unskilled chump labor, fix leaks and every manner of repair (even plumbing) with more ‘plaster and paint’ to conceal it, and cut every corner imaginable. Of course, that’s why the ceiling collapsed.

One problem at the outset is I am 100% certain that when the first latex coats were painted over the oil decades back, no primer was used. In some areas, the thick coats of latex could be almost peeled off the wall, as there is a very poor bond to the oil substrate.

Prior to skimming I observed the prep work. In some areas they scraped the loose plaster/paint but not 100%…just where it came off easily with a knife. Often this scraping revealed an old oil coat layer with a fair amount of sheen to it, perhaps originally an eggshell or even semi-gloss. That was the only prep work, at best…and other rooms got even less, or no prep work at all. The walls were not deglossed, or cleaned with TSP or other cleanser, or even wiped off with a dry cloth to remove dust. In a hallway, which had numerous thick layers of semi-gloss latex paint, the walls were not prepped AT ALL. No cleaning, no wiping of dust even. Nothing. The skim went directly onto this unprepped substrate.

I am not the owner and I am not paying for the work. The collapsed ceiling is getting repaired only because I sued the owner. The owner did the skim coating voluntarily it was his idea.

I observed and commented to the contractor and his workers the necessity to do one or more of the following: a) scrape all old latex paint off to the depth of the unprimed interface between oil/latex, b) sand or use liquid deglossing agent, c) clean thoroughly with TSP or other suitable cleanser and rinse if necessary, d) apply a bonding agent to the wall (PlasterWeld, etc), d) mix a bonding agent into the mud.

The contractor said he knew what he was doing and he left the scene, rarely returning except to give directives to his workers. The workers looked at me and shock their head yes when I commented on potential bonding issues and how prep, then they went ahead and ignored me: they didn’t do any of this.

Instead they mixed about 25% plaster Paris into USG Green label premix JC. I suggested Durabond as a first coat, but the contractor said he preferred to use this mix as he’s familiar with it and it works for him.

The mud guys as I said have very good hand skills. They toweled, knifed, and sanded and got some nice results, one room easily a level 5. The contractor is the one used for all this owner’s buildings, so I was willing to accept he knew what he was doing with regard to the skim coat on these wall types. And as I said, the wall looked good.

I stripped the doors, molding and trim, caulked, then primed and painted with Ben Moore First Coat/Regal line.

This was between about 4-5 months ago (some rooms less than that). As predicted, the hallway skim coat, which received zero prep, is failing. A network of dispersed cracks is appearing. Some cracks are still under the surface while others have broken through. Some areas the skim coat is pulling away from the substrate and cracking. On other areas that to the eye look fine, if I drag my fingernail or tap with my fingernail, I can hear the sound difference where there is a gap behind the skim coat where it is separating from the wall. In some areas a large area (approx. 12” in dia.) although not cracked, has pulled away from the substrate and I can push it back against the substrate about 1/16”-1/8”…there’s an air pocket behind it suggesting a failed bond. With winter here in NYC and lots of heat and lower humidity in the apartment, the problems are accelerating.

That’s the situation. Again, I’m not familiar with plaster, painted/plaster substrates and want some feedback. Based on what I’ve written, would you say that this skim coating was unprofessionally and/or incompetently done? The contractor had returned once to patch a few areas, but each week more and more cracks appear and he does not want to redo the job. In my opinion the place is a ticking time bomb for this skim coat to crack and delaminate, and I dread having to vacate those rooms again and deal with the workers and dust on a redo.
 

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Of course it was done improperly a bonding agent absolutely should have been used as well as addressing any cracks with mesh before skim coating. All too often contractors take the same short cut that was used in your case. BTW when plastering there should be no sanding which means no dust. if they are sanding then it ain't plastering.
 

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:thumbsup::thumbsup::thumbsup:
Of course it was done improperly a bonding agent absolutely should have been used as well as addressing any cracks with mesh before skim coating. All too often contractors take the same short cut that was used in your case. BTW when plastering there should be no sanding which means no dust. if they are sanding then it ain't plastering.
 

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Failed skim coat situation.

I have my own suspicions, but wanted to get some feedback from those with more experience with plaster rather than sheetrock. I have a professional background with sheetrock and painting, but very little with plasterwork.

I live in an apartment (long term renter) with plaster/wood lathe construction. There’s been construction here to repair a collapsed ceiling due to joist failure from water damage (I was not the contractor). During this construction the owner agreed to skim coat several other rooms, which due to the decades of neglect and were not looking so good. This was a mini renovation of sorts.

The contractor doing the skimming is not licensed with my city (though no license required for work not requiring a permit, such as skimming). He had the usual illegals doing the actual work. The workers were very good mud guys at least with regard to their hand skills. However these walls are 80 years old, have numerous old coats of oil paint and also have numerous coats of latex/acrylic paint over the oil. This is par for the course in an apartment like this in NYC where landlords in apartment buildings looking for a quick buck with no money layout use the cheapest paint possible, unskilled chump labor, fix leaks and every manner of repair (even plumbing) with more ‘plaster and paint’ to conceal it, and cut every corner imaginable. Of course, that’s why the ceiling collapsed.

One problem at the outset is I am 100% certain that when the first latex coats were painted over the oil decades back, no primer was used. In some areas, the thick coats of latex could be almost peeled off the wall, as there is a very poor bond to the oil substrate.

Prior to skimming I observed the prep work. In some areas they scraped the loose plaster/paint but not 100%…just where it came off easily with a knife. Often this scraping revealed an old oil coat layer with a fair amount of sheen to it, perhaps originally an eggshell or even semi-gloss. That was the only prep work, at best…and other rooms got even less, or no prep work at all. The walls were not deglossed, or cleaned with TSP or other cleanser, or even wiped off with a dry cloth to remove dust. In a hallway, which had numerous thick layers of semi-gloss latex paint, the walls were not prepped AT ALL. No cleaning, no wiping of dust even. Nothing. The skim went directly onto this unprepped substrate.

I am not the owner and I am not paying for the work. The collapsed ceiling is getting repaired only because I sued the owner. The owner did the skim coating voluntarily it was his idea.

I observed and commented to the contractor and his workers the necessity to do one or more of the following: a) scrape all old latex paint off to the depth of the unprimed interface between oil/latex, b) sand or use liquid deglossing agent, c) clean thoroughly with TSP or other suitable cleanser and rinse if necessary, d) apply a bonding agent to the wall (PlasterWeld, etc), d) mix a bonding agent into the mud.

The contractor said he knew what he was doing and he left the scene, rarely returning except to give directives to his workers. The workers looked at me and shock their head yes when I commented on potential bonding issues and how prep, then they went ahead and ignored me: they didn’t do any of this.

Instead they mixed about 25% plaster Paris into USG Green label premix JC. I suggested Durabond as a first coat, but the contractor said he preferred to use this mix as he’s familiar with it and it works for him.

The mud guys as I said have very good hand skills. They toweled, knifed, and sanded and got some nice results, one room easily a level 5. The contractor is the one used for all this owner’s buildings, so I was willing to accept he knew what he was doing with regard to the skim coat on these wall types. And as I said, the wall looked good.

I stripped the doors, molding and trim, caulked, then primed and painted with Ben Moore First Coat/Regal line.

This was between about 4-5 months ago (some rooms less than that). As predicted, the hallway skim coat, which received zero prep, is failing. A network of dispersed cracks is appearing. Some cracks are still under the surface while others have broken through. Some areas the skim coat is pulling away from the substrate and cracking. On other areas that to the eye look fine, if I drag my fingernail or tap with my fingernail, I can hear the sound difference where there is a gap behind the skim coat where it is separating from the wall. In some areas a large area (approx. 12” in dia.) although not cracked, has pulled away from the substrate and I can push it back against the substrate about 1/16”-1/8”…there’s an air pocket behind it suggesting a failed bond. With winter here in NYC and lots of heat and lower humidity in the apartment, the problems are accelerating.

That’s the situation. Again, I’m not familiar with plaster, painted/plaster substrates and want some feedback. Based on what I’ve written, would you say that this skim coating was unprofessionally and/or incompetently done? The contractor had returned once to patch a few areas, but each week more and more cracks appear and he does not want to redo the job. In my opinion the place is a ticking time bomb for this skim coat to crack and delaminate, and I dread having to vacate those rooms again and deal with the workers and dust on a redo.
I got some advice for you.....save yourself the headaches
HIRE A PROFESSIONAL, bill your landlord. It obvious you don't have a clue.
 

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Discussion Starter · #7 · (Edited)
Big thanks to all for the replies.

Fenez:
You are correct it's not traditional 'plastering' by any means but rather a hybrid fix with different materials.

joepro0000:
Can you please elaborate (btw, this is for walls and ceilings)? You're saying that after scraping they should have applied primer over the substrate before applying the JC? An alkyd base primer? This in addition to, or in substitution of, a bonding agent? I know there's different schools of thought on this.

Btw, I failed to mention that cracks generally were treated with mesh tape, however, cracks were not grooved out before applying the tape, nor were deep cracks addressed by an 'inverted 'V' groove' down to the wood lathe to provide a key-lock for the patch material. However, most of the cracking appears to be surface cracks to the skim coat and not from deeper structural cracks in the plaster substrate, except for a few limited exceptions. The contractor said he was going to spread mesh sheet across the entire ceiling (he didn't use any).

d-rock:
You are jumping into the breech: I'm clued in, please read below.


I wanted some confirmation and consensus, or corrections to my suspicions regarding proper procedures.
There have already been a few lawsuits regarding repairs to my apartment (but not this skim coat fiasco) including NYC suing my landlord with contempt charges. These lawsuits resulted in forcing the landlord to undertake the construction/repair work in the first place (serious structural issues involving failed joists completely severed by water leaks and a ceiling collapse).
Unfortunately, I do NOT have the right to bring in my own workers...at least not at this stage. That would make me vulnerable to liability and charges of obstruction of court orders or denial of access (the lawyers would twist it into that). FYI, I've already been sued in Supreme Court, frivolously by this (crook) landlord for false charges of obstructing access and $125,000 damages, he lost that case, and he lost three other lawsuits directly related to these issues.
Hiring my own contractors or doing it myself is not a legal option in this situation, at least not at this stage. What I can do, is demand the work be corrected. If the landlord refuses, I can sue him to make repairs to the cracked walls and bring evidence of the failing skim coat and also introduce professionals as witnesses to testify that the skim coat was incompetently performed using unorthodox and inadequate procedures, and that the trade that has a long history of proven methods that work, and there are other methods that do not work, are considered unprofessional, inadequate, and incompetent.

I know there's more than one way to skin a cat and skim coat a wall. Before I proceed, I want to be certain that the methods his contractor used are universally disdained by professionals in the trade...rather than discovering that his methods are commonly employed by professionals and with successful results. So please, anyone reading with a professional background in this area, please reply with your profession opinion, it's greatly appreciated.

My landlord is a disbarred attorney. He's cheap, dishonest, deceptive, smart, and fails to assume responsibility always preferring instead to litigate. In NYC with the rental market so expensive and rent regulation, this sort of character is a common occurrence.

What is painful is to see a beautiful place abused by chumps who do not take pride in their trade or their craftsmanship. Even more, I would have loved to see a traditional three stage plaster repair. Seems tradesmen specializing in the latter are a dying breed these days.

Thanks again guys.
 

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Discussion Starter · #8 ·
After scraping and revealing various layers of paint, is it best to apply a primer over this substrate before applying the JC? If yes, what's recommended: alkyd base primer or something like Zinsser 123? Or, should the bonding agent (like Plaster Weld) be painted on the wall instead of a primer? Or is it best to use both: a coat of primer followed by a thin coat of bonding agent? I know there's different schools of thought on this. What have you guys used with success?

They may be coming in shortly to redo this and I'd like to pass on the best info I can to assure a successful job rather than just trying to conceal the problems.

Thanks a bunch.
 

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Okay

Scrape off and out everything that is loose . V out all the cracks, use a bonding agent now for adhesion. Fill V,s with Eay-sand 90 and immeadiately tape with mesh. First coat with Easysand 90 and all other coats with a topping mud. Sand and prime. Wa La"
 

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The main purpose of primer is for paint to stick to the wall. If you paint directly without primer on drywall, the paint will eventually fall off. Same thing would apply if your talking about a bunch of patch work on an already painted surface that been painted years ago. I would use Kilz - latex (Kilz 2) alot of painting stores say its the best primer, but really an over-kill. However its the same cost of a SW or BM primer, just about. A bonding agent would only need to be applied if using a 1-coat stucco or plaster. But your talking about durabond and veneer finish, which is pretty weird. I would of used durabond with reg. J.compond instead. Has never failed us.
 

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Some important things: (Using always the correct materials, giving always the right time )

The first one, is scrape off everything until nothing absolutly nothing is loose on the walls. Second , make sure you use mesh tape in every single crack, third one , very important " when doing the first coat use easy sanding or durabond,and of course do not forget that depending on how big is the job you will chosse wich to use 45 minutes, or 90 minutes,after your first coat is dry give another coat and depending of how it looks after sanding, you as a painter will know what to do. Good luck !
 

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Discussion Starter · #13 · (Edited)
Thanks for the replies.

Of course, I know that a setting type compound is much much better for this application (as it has an integral bonding agent mixed in and less shrinkage than JC); but there are those out there that skim coat with pre-mix JC and this contractor likes to use green label JC with some plaster of paris mixed in (you can lead a horse to water...). That's why I ask about the bonding agent.

From my limited experience, when using Durabond/Easysand then one doesn't need to use a bonding agent because they are formulated with a bonding agent mixed in, that's one quality that sets them apart from products like traditional plaster.

But when using the JC + plaster method, how best to prep the surface after scraping the loose stuff off? I ask about primer (not for use under the top coat of paint as that goes without saying, but under the skim coat) because I recall being told at one time that a good primer can perform like a bonding agent to better allow JC to stick to the various paint layers on a freshly scraped wall.

One other point: the contractor mentioned that the JC skim coat reacts with the underlying old paint layers (and plaster) and there is a moisture transfer that takes place and that can cause the cracking and failure of the new skimcoat. If this is the case, how is this prevented?
 

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Don't mix plaster with regular compound, ever. Some here will tell you they do it and it works for them. Fine and good, but it voids whatever warranty the JC maker offers. Says it right on the bucket/ box. Ask yourself, would you put any amount of deisel in your unleaded vehicle? And then tell your mechanic, "well some guy told he does it all the time and never has a problem". Call or email USG and see what they say about field experiments like this.
 

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Discussion Starter · #15 ·
Thanks again for all the informative replies.

[email protected]:
You are absolutely correct and the mixing of plaster into the joint compound sent off alarms in my head. It is nothing more than a field experiment and thanks for pointing out that it voids the JC makers warranty. Clearly an unprofessional technique.


Do you or anyone else know if there is a technical term common in the trade which describes the condition when the skim coat separates from the substrate? This appears to be the symptom of most of the failing skim coat here: it's where cracks have not yet formed but the thin skim layer is pulling away from the substrate and I can feel (and hear when tapping with my fingers) that it's hollow behind the skim coat. In some larger pancake size areas I can actually push the skim coat in about 1/16" -1/8" and it pops back out, there's a shallow air pocket behind it where it's lost its bond to the substrate....but no visible cracks. If I just run my fingernail against the wall I can hear the differences where the skim coat has lost its bond.

???
 

· The Drywall King!
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Like I said in the past, sand JC compound off the wall, scoup up the dust, add water to the dust, and you got durabond, except its just missing the chemical to speed up the drying. Same thing. Between me and my finishers, we have over 20 years mixing durabond and jc and never had 1 problem. I don't think its an experiment, its a pro's trick.
 
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