# paint finish failing over skimcoat



## bigjeffie61520 (Oct 3, 2009)

did a job where wallpaper was stripped and painted w/o adhesive removed ( not me )

paint looked ok but was lumpy.

did a lot of sanding to knock down the high spots. 
sealed w/ guardz

skim coated, sanded- looked good

sealed w/ zinnser BIN ( tinted 4 topcoat )

all was looking great

applied 2 coats BM natura eggshell

looking good

2 days later the paint is cracking, far worse than the worst of the original.

looks like dryig mud puddle, but microscopic, can only be seen if you look hard from the right angle of light

was the BIN incompatible w/ the Guardz ?

guardz has ammonia, which is a solvent for BIN

didnt notice until I was looking for the cause

Am i totally screwed?

do i have to sand everything off and start over?

if what i have now is failing. i dont see how i can salvage any of it

any ideas guys?

i feel like an idiot now for mixing the primers

whatever I do now i need a permanent solution

thanks 4 help


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## ProWallGuy (Apr 7, 2007)

I would bet the mud wasn't completely dry, and you sealed in the (escaping) moisture with the BIN. It wasn't hot mud, was it? Hot mud doesn't play nicely with many primers at all.

If it still feels solid, skim coat again to fill the cracks, let dry (make sure it is fully dry) then prime it with an acrylic primer then paint.

My 2 cents.


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## Last Craftsman (Dec 5, 2008)

My instinct set off a an alarm when you said you put shellac on top of sheetrock mud.

I don't know why, I have never actually done that, so I can't say from experience that it doesn't work.

However, it seems like it would be too brittle/not soak into the mud far enough/not seal it uniformly.

It also seems like it would have the tendency to do what mud does when you use a shiny topcoat as a primer, which is soak in differently everywhere, then when you paint over that, you can still see the non-uniformity caused by the first coat soaking in unevenly.

In any case, I would stick with PVA or equivalent whenever applying first coat over new mud/wallboard. If there are some stains bleeding through, I would seal them AFTER you prime the mud with PVA.


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## plainpainter (Nov 6, 2007)

This is the same cracking you see when you paint over caulking before it's cured well enough - or if you used a rock hard enamel over a flexible coating like maddog. Are you a professional? Personally I think sealing the wall with guardz, then mudding and priming again was a waste a time. You should have just mud it direct to the wall with wallpaper glue and all - joint compound sticks to anything. After you sanded that stuff down and got the desired smoothness - then you can seal it, I would have used oil based primer - cover stain or oil based kilz is fine. That would have been a perfect finish. 

Not to mention everyone is so guardz crazy around here - it seems like a slightly wacky off the beaten track primer to use - how do you know it was compatible with the topcoats - especially BIN - for crying out loud, who uses BIN for other than the most tricky priming situations like sealing knots or water stains? Heck, I've used it as an interior primer for wood sometimes - but in general I use primers that are more "bread 'n butter" to the task at hand. Heck I'd be worried if natura didn't react fine with guardz undercoat, if I never tried the combo before - you never know these days at the lightning rate they are turning out new technology products.


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## Mantis (Aug 4, 2008)

plainpainter said:


> Are you a professional? Personally I think sealing the wall with guardz, then mudding and priming again was a waste a time. You should have just mud it direct to the wall with wallpaper glue and all - joint compound sticks to anything.
> Not to mention everyone is so guardz crazy around here - it seems like a slightly wacky off the beaten track primer to use


A little harsh? haha. This is exactly the method i use when stripping wallpaper. 
1> Remove paper
2> Sand residual glue
3> Seal with Gardz
4> Patch/skim as needed
5> Prime walls
6> Paint as normal

Imo, Gardz is not a "wacky off the beaten track primer". It's a drywall conditioner than seals in wallpaper glue and damaged drywall. Sure, it's not required on every paper removal, but it's wonderful when the drywall paper has been compromised or there is an abundance of glue residue remaining. It's not quite the same as slapping a coat of oil primer on the wall. This stuff goes on like water and dries like a hardened glue, sealing everything under it. Awesome stuff. </gardzprotector> :thumbsup:


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## plainpainter (Nov 6, 2007)

I could only see a need for a guardz like product if wallpaper was hung directly to non-finished drywall. Other than that - I have done a fair share of veneer plaster walls with residue of glue - mud as needed, sand and prime over everything with an oil to seal the surface.


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## bigjeffie61520 (Oct 3, 2009)

ProWallGuy said:


> I would bet the mud wasn't completely dry, and you sealed in the (escaping) moisture with the BIN. It wasn't hot mud, was it? Hot mud doesn't play nicely with many primers at all.
> 
> If it still feels solid, skim coat again to fill the cracks, let dry (make sure it is fully dry) then prime it with an acrylic primer then paint.
> 
> My 2 cents.


 
i used lightweight compound, whipped it up w/ a drill and a paddle.

i added some water to make it slip, but went on nicely w/ a 12' knife. i would have had to go out of my way to get another gallon of guardz to seal the skim. let me tell you how much I regret it

i have used a lot of bin on this project, for priming oil painted doors, jambs, and base before applying latex semi-gloss

i have sealed all of my drywall patches and point up w/ bin, and had excellent results

it makes sense that the skim may have been a bit wet, as the guardz would force all of the moisture to evaporate through the surface

the checking/ cracking is most pronounced in the areas where the skim was deepest

i dont mind skimming , resealing, and painting it again ( relatively speaking )
but i was concerned that what i have now would continue to deteriorate, to the point of delaminating paint failure, and ultimately reappear in the surface 

this house is 42 yrs old


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## chrisn (Jul 15, 2007)

Mantis said:


> A little harsh? haha. This is exactly the method i use when stripping wallpaper.
> 1> Remove paper
> 2> Sand residual glue paste
> 3> Seal with Gardz
> ...


 
Paste pleasr not glue:yes:


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## venetian designs (Nov 24, 2007)

Any chance that gardz wasn't completely dry when you skim coated it? That could possibly cause some cracking as the mud/primer/finish were drying over semi-wet gardz.


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## ewingpainting.net (Jun 2, 2008)

It sounds to me it could be a primer issue, can also be from the outer layer drying to fast, or be what Scott suggested. Can never know unless it is seen. Got Pics?


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## bigjeffie61520 (Oct 3, 2009)

venetian designs said:


> Any chance that gardz wasn't completely dry when you skim coated it? That could possibly cause some cracking as the mud/primer/finish were drying over semi-wet gardz.


the guardz was dry overnight

i will see it again monday- try to get some photos

the HO is aware of the issue and not over reacting ( they are very happy w/ the rest of the work I have done )


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## deach (May 11, 2008)

ProWallGuy said:


> I would bet the mud wasn't completely dry, and you sealed in the (escaping) moisture with the BIN. It wasn't hot mud, was it? Hot mud doesn't play nicely with many primers at all.
> 
> If it still feels solid, skim coat again to fill the cracks, let dry (make sure it is fully dry) then prime it with an acrylic primer then paint.
> 
> My 2 cents.


I gotta go with Pro wall on this one. The key was when you said it's happening where the repairs were the "deepest". My 2 cents too .......


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## AmericanPatch&Paint (Dec 5, 2009)

If your mixing your mud w/ a paddle/drill you should not have to add water when skimming (your just adding more moisture content), especially when your applying anything more than a skim coat (thicker areas)
~use a paddle mixed+3
~or use a slightly diluted paddle mixed topping
~sand
~prime w/ drywall filler/sealer primer, or Guardz
~paint
~:thumbup:


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## bigjeffie61520 (Oct 3, 2009)

AmericanPatch&Paint said:


> If your mixing your mud w/ a paddle/drill you should not have to add water when skimming (your just adding more moisture content), especially when your applying anything more than a skim coat (thicker areas)
> ~use a paddle mixed+3
> ~or use a slightly diluted paddle mixed topping
> ~sand
> ...


not sure what a paddle mixed plus3 is


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