# why primer is bubbling up over wall paper



## Zeebo (Jul 4, 2005)

I was on a work site last week doing some taping and noticed a painter applying an oil base primer (Zinnser Cover Stain) to a wall that had wall paper on it. He removed most of the wall paper..but some remained on (small patches). The purpose of removing the wall paper was to prime the wall and put a skim coat of Sheet rock 45 on it. Paint would follow. As soon as the painter applied the primer, the pieces of wall paper that he left on started to bubble up...almost instant. Never have seen something like this before. This would have been great as a high school science project!! The walls were in pretty bad shape too as they still had some wall paper adhesive. So it made me wonder about a number of things.....

(1) Can you apply primer on to wall paper and follow it up with painting it???If the answer is yes, what kind of primer (Bin 123 bulls eye?)

(2) Why did the wall paper bubble? Was it due to the oil paint??

(3) Can you apply drywall compound to a surface (skimming it to make it smooth) that has wall paper on it and has been primed. Assume that the wall paper has not been removed?

(4) Finally. Let's say the wall paper was completely removed and the surface had some remaining wall paper adhesive on it. Can you apply a primer over the surface followed by dry wall compound (after primer drys!)

As always, thanks for your suggestions and education. 

Zeebo


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## AAPaint (Apr 18, 2005)

1. Yes, you can prime and paint over wallpaper. Is it a recommended prosess, NO. Any quality primer is fine IMHO, because it all really depends on how good the adhesion of the wallpaper is. If it's not holding allready, paint will lift it.

2. Yes, it was due to the oil. First, oil paints tend to soak in deep, which will lift wallpaper, and can also lift any areas of peeling paint that aren't sanded back tight to the surface. Seen it 1,000 times. Also, oil paints are solvent based, and the solvents can cause the glue to loose adhesion. Anything that isn't bonded will lift when oil based paints are applied, especially the slow dry variations. 

3. Yes on this as well. Again, it all depends on how well the wallpaper is holding up to begin with. Painting over wallpaper isn't something I recommend, but if a customer wants it........

4. NO! All adhesive must be removed. Paint does not hold well to wallpaper adhesive or any other glues. You should always paint only once the surface is fully cleaned. If you want the paint to last, don't paint over old adhesive.

I don't believe too much in painting over wallpaper, but like many others I'm sure, I have painted my share of wallpaper. I never warranty a finish over wallpaper, it's too much liability if it all starts to fall down. IMO, that painter should have made sure the surface was properly cleaned, and if he didn't expect that stuff to lift when he hit it with oil, he has no clue.


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## Zeebo (Jul 4, 2005)

AAPaint said:


> 1. Yes, you can prime and paint over wallpaper. Is it a recommended prosess, NO. Any quality primer is fine IMHO, because it all really depends on how good the adhesion of the wallpaper is. If it's not holding allready, paint will lift it.
> 
> 2. Yes, it was due to the oil. First, oil paints tend to soak in deep, which will lift wallpaper, and can also lift any areas of peeling paint that aren't sanded back tight to the surface. Seen it 1,000 times. Also, oil paints are solvent based, and the solvents can cause the glue to loose adhesion. Anything that isn't bonded will lift when oil based paints are applied, especially the slow dry variations.
> 
> ...



thanks for the detailed response...very informative...PS...I was not the painter if you were wondering...I would have removed the wall paper. Cheers


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