# Screw Stains



## Pete Martin the Painter (Nov 8, 2012)

Anybody ever see this before. All over the house. And there are tons of them. We (the HOs and myself) think it was a DIY project and some how the screws or nails rusted. My plan is to sand skim coat (a lot of them are indented) and prime with Cover Stain. Anybody approach this differently?


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## AngieM (Apr 13, 2016)

I would spot prime each nail with some aresol oil based Problock before I skimmed it to stop it from bleeding through the mud.


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## PRC (Aug 28, 2014)

I have seen it,or similar, once before. I found it was dust/airborne contaminates that had been attracted to the screws. Then, last year, Gough posted the answer in a similar thread. IIRC, it had to do with insulation and air movement which cause a thermal effect on the screws and made the airborne particulates attracted to them. Not sure if I got that exactly right or if it's the same thing happening in your situation. We had no problem painting over them without priming. If it is the same problem we saw then it will continue to happen.


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## Sir Mixalot (Sep 8, 2009)

It's called thermal bridging.:thumbsup:

https://en.wikipedia.org/wiki/Thermal_bridge



> A thermal bridge, also called a cold bridge or heat bridge, is an area of an object (frequently a building) which has a significantly higher heat transfer than the surrounding materials resulting in an overall reduction in thermal insulation of the object or building.[1] Thermal bridges occur in three ways, through: materials with higher thermal conductivity than the surrounding materials,[2] penetrations of the thermal envelope, and discontinuities or gaps in the insulation material.[1]
> 
> Thermal bridging in buildings reduces energy efficiency and can allow condensation (moisture) and thermal comfort problems. Condensation can result in indoor air quality problems and building deterioration.
> 
> Thermal bridging is prevented by careful design applying materials to achieve a uniform thermal resistance such as thermal breaks and continuous insulation.


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## Sir Mixalot (Sep 8, 2009)

AngieM said:


> I would spot prime each nail with some aresol oil based Problock before I skimmed it to stop it from bleeding through the mud.


I would say lightly spray them or you run the risk of sealing the surface to much causing those spots to flash through the top coat.

Edit- Didn't see the skimming part. I don't think either will fix it in the long term.


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## RH (Sep 7, 2010)

And here I thought this thread was going to be a rant about poor performing brands of wood stains.


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## DeanV (Apr 18, 2007)

Me too, RH. But, like everyone else said, it will come back. Paint and primer can't fix it.


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## Pete Martin the Painter (Nov 8, 2012)

DeanV said:


> Me too, RH. But, like everyone else said, it will come back. Paint and primer can't fix it.


Not even Bin?


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## DeanV (Apr 18, 2007)

It forms because the screw heads are colder than the surrounding wall area. So, BIN may seal the stain, but it will come back in time as dust and dirt are attracted to those spots.


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## Epoxy Pro (Oct 7, 2012)

Sir Mixalot said:


> It's called thermal bridging.:thumbsup:
> 
> https://en.wikipedia.org/wiki/Thermal_bridge


We have seen this so bad there were black stripes running the length of the ceiling or wall. We used an oil based stain blocker.


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## Epoxy Pro (Oct 7, 2012)

DeanV said:


> It forms because the screw heads are colder than the surrounding wall area. So, BIN may seal the stain, but it will come back in time as dust and dirt are attracted to those spots.


All the checking around I did it seems to point to either poor insulation or screws made in Chine. I am leaning towards the bad insulation job.


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## lilpaintchic (Jul 9, 2014)

Isn't that commonly known as "ghosting"? I can't really see much in the pics.


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## lilpaintchic (Jul 9, 2014)

Pete the Painter said:


> Anybody ever see this before. All over the house. And there are tons of them. We (the HOs and myself) think it was a DIY project and some how the screws or nails rusted. My plan is to sand skim coat (a lot of them are indented) and prime with Cover Stain. Anybody approach this differently?


Can't really see from the pics if there is rust involved or if it's just "ghosting". If there's rust, a spot prime is a good idea. If not, just slap 2 coats of finish on and be done. It's not something that typically bleeds through. It's an anomaly that occurs and over time will reoccur. It's definitely a building issue vs. A paint issue....if you really want to prime it, I'd use 123 (tinted to 50% of finish color)or similar. Not oil.

If there is rust, I'd be looking for a leak somewhere.


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## PACman (Oct 24, 2014)

Wow! I was way off om this one! I was thinking Scotchgard.


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## Sir Mixalot (Sep 8, 2009)

lilpaintchic said:


> Can't really see from the pics if there is rust involved or if it's just "ghosting". If there's rust, a spot prime is a good idea. If not, just slap 2 coats of finish on and be done. It's not something that typically bleeds through. It's an anomaly that occurs and over time will reoccur. It's definitely a building issue vs. A paint issue....if you really want to prime it, I'd use 123 (tinted to 50% of finish color)or similar. Not oil.
> 
> If there is rust, I'd be looking for a leak somewhere.


It's more like a soot stain. Latex stain blockers will not make it go away in most cases.


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## lilpaintchic (Jul 9, 2014)

Sir Mixalot said:


> It's more like a soot stain. Latex stain blockers will not make it go away in most cases.


You can't make it "go away". It's re occuring. Sure, I see the logic in oil if it's really old and black, but not if it's the typical 10-20 yr old discoloration. An average quality paint will do the job absent of primer. There's no greasy soot, it's just average grime/dust accumulation. My mom's place has that issue. Painted the vaulted lid with either eminence or ?? Something in that range about 8 yrs ago...it's just barely starting to accumulate again...no primer.it'll paint it again in a couple of years or so. Oil is overkill imo. Just makes us "feel" better but doesn't actually do anything special in this circumstance imnsho....heck, if you really want to prime it, you could probably gardz it but 123 is cheaper and builds for a better finish imo. I don't use oil over pencil lead or chalk either.


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## Sir Mixalot (Sep 8, 2009)

lilpaintchic said:


> You can't make it "go away". It's re occuring. Sure, I see the logic in oil if it's really old and black, but not if it's the typical 10-20 yr old discoloration. An average quality paint will do the job absent of primer. There's no greasy soot, it's just average grime/dust accumulation. My mom's place has that issue. Painted the vaulted lid with either eminence or ?? Something in that range about 8 yrs ago...it's just barely starting to accumulate again...no primer.it'll paint it again in a couple of years or so. Oil is overkill imo. Just makes us "feel" better but doesn't actually do anything special in this circumstance imnsho....heck, if you really want to prime it, you could probably gardz it but 123 is cheaper and builds for a better finish imo. I don't use oil over pencil lead or chalk either.





Sir Mixalot said:


> *I don't think either will fix it in the long term.*





Sir Mixalot said:


> It's more like a soot stain. Latex stain blockers will not make it go away *in most cases*.


I've already acknowledged that it will come back and I also said "in most cases" you will need oil stain blocker but not all.

It's been my experience on many homes and years of doing this that the black bleeds through with latex paint and latex primer. Maybe because usually these customers homes have gone awhile without being painted and these areas prompted them to paint. But,the black is very BLACK.

And a lot of the times it's not just the screws but the entire framing member is black. Maybe it's a regional thing because I'm in florida. IDK. 

I know my Mom would be a lot more forgiving with the stains. But after explaining to my customers what it is and that spot priming and paint will make it temporarily go away, it will be back. I must make sure that these areas are completely gone for the time being to hold up my end of the bargain. So the oil base stain blocking primer is my little insurance policy...:thumbsup:


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## Sir Mixalot (Sep 8, 2009)

Pete the Painter said:


> Anybody ever see this before. All over the house. And there are tons of them. We (the HOs and myself) think it was a DIY project and some how the screws or nails rusted. My plan is to sand skim coat (a lot of them are indented) and prime with Cover Stain. Anybody approach this differently?


Pete, I can also tell you by the looks of the screws in the photo. There appears to be dimpling around them. What that means is that this particular ceiling is sagging and the screws are staying in place creating a dimple. Possibly from a water intrusion issue. So it could be a combination of rust and thermal bridging you are seeing.


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## lilpaintchic (Jul 9, 2014)

Sir Mixalot said:


> I've already acknowledged that it will come back and I also said "in most cases" you will need oil stain blocker but not all.
> 
> It's been my experience on many homes and years of doing this that the black bleeds through with latex paint and latex primer. Maybe because usually these customers homes have gone awhile without being painted and these areas prompted them to paint. But,the black is very BLACK.
> 
> ...


Ok...
And while my mom would be forgiving, my point was that I've been able to see the progression over the years since she bought it. Believe me, if I thought oil was a viable solution there, it'd be a no brainer. That's the last lid I wanna keep repainting. For free. Her's certainly was not as bad as others I've seen and heard about. 

Eh...it takes a fair amount of discretion I guess as to how bad is it, and prime/no prime. Solvent or wb....experience is the best teacher for most of us.


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## PACman (Oct 24, 2014)

Marquee ceiling paint. One coat.


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## slinger58 (Feb 11, 2013)

RH said:


> And here I thought this thread was going to be a rant about poor performing brands of wood stains.





PACman said:


> Wow! I was way off om this one! I was thinking Scotchgard.


Obviously my first thought about the thread title was more in line with what Pacman was thinking. Scotchgard. Lol.


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## Pete Martin the Painter (Nov 8, 2012)

lilpaintchic said:


> Can't really see from the pics if there is rust involved or if it's just "ghosting". If there's rust, a spot prime is a good idea. If not, just slap 2 coats of finish on and be done. It's not something that typically bleeds through. It's an anomaly that occurs and over time will reoccur. It's definitely a building issue vs. A paint issue....if you really want to prime it, I'd use 123 (tinted to 50% of finish color)or similar. Not oil.
> 
> If there is rust, I'd be looking for a leak somewhere.


Most likely not rust because it is all over the 2nd floor of the house.


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## Pete Martin the Painter (Nov 8, 2012)

Sir Mixalot said:


> Pete, I can also tell you by the looks of the screws in the photo. There appears to be dimpling around them. What that means is that this particular ceiling is sagging and the screws are staying in place creating a dimple. Possibly from a water intrusion issue. So it could be a combination of rust and thermal bridging you are seeing.


There is dimplimg in many areas.


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## TrueColors (Jul 30, 2010)

I see it all the time where I live. But way worse. We have lots of ghosting or stud shadowing is what I call it. I always thought it was from poor vapour barrier Install or none for that matter. I always prime and paint with no issues returning so far.


Sent from my iPhone using Tapatalk


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## lilpaintchic (Jul 9, 2014)

slinger58 said:


> Obviously my first thought about the thread title was more in line with what Pacman was thinking. Scotchgard. Lol.


You two....smh.lol


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