Knockdown over painted popcorn?


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Old 01-07-10, 07:17 AM
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Knockdown over painted popcorn?

Hello,

I've got a 1965 south FL home. I'm in the process of re-doing the kitchen and want a knockdown texture on the ceiling. About 75% of the kitchen ceiling is covered with "baby" painted popcorn and is up there really good. The other 25% is finished 5/8" drywall that I just installed.

Is it possible to skim coat the painted popcorn and spray knockdown on top of the entire ceiling? If so, how smooth does the skimcoat need to be as I'm not a master with a mud knife yet.

I don't know (and kind of don't want to know) if the popcorn contains asbestos and I know scraping painted stuff is a real hassle - especially if it contains asbestos. Any insights or other ideas you can offer are greatly appreciated!

Thanks!!

- Joe
 
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Old 01-07-10, 08:28 AM
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Its tough to say with out seeing it first hand but if it is not too bumpy you could just skim it.
I did exactly what you are talking about. My ceilings were textured and painted a few times. I just scraped as best as I could, skimmed it twice with a light sand in between. My knock down is not very thick so I wanted to get a smooth start.
 
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Old 01-07-10, 08:41 AM
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Thanks for the information! I could take a picture of the ceiling and post that, would that help?

Thanks again!!

- Joe
 
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Old 01-07-10, 01:52 PM
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Pics almost always help

Popcorn comes in 3 sizes [fine, medium and coarse] How it was applied can also be a factor. Sometimes it's applied fairly thin other times it might have been sprayed real heavy.

Generally it's best for the entire ceiling to be fairly uniform as differences in the drywall can affect how the texture looks.

Asbestos texture is only hazardous in dry powder form. Sanding and scraping while it's dry is bad. If you keep the asbestos wet and contain the debris - there isn't much danger to your health. Commercial popcorn prior to the late 70's was almost always laced with asbestos [fire retardant] Not all residential popcorn has asbestos but there is no way to tell for sure without testing.
 
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Old 01-07-10, 02:07 PM
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Here are a few close-up pics:











Would you guys agree this is small/baby popcorn?

If it makes any difference, the popcorn appears to have been applied to drywall in a few places, but most of it appears to be on top of a light brown cement-like substrate of some kind - perhaps a plaster skim-coat?

I have a fairly serious microscope that I bought a few years ago. By my calculations, any asbestos fibers should be visible at about 400x magnification. I examined a few samples at 400x and 800x and saw maybe 1 long, thin fiber. Then again, I don't have one of those polarized light microscopes that the pros use so I'm not sure how accurate my results are.

Thanks,

- Joe
 
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Old 01-07-10, 02:48 PM
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You should be able to mud over the popcorn but it's best to scrape it first. Any loose kernals will get in the wet mud and be a royal pain. Also the more popcorn you remove, the easier the skim coat process will be. With the texture remove, 1 coat of mud should work but mudding over the texture will take several coats.

While I sprayed a good bit of asbestos back in the 70's, I wouldn't have a clue as to how to identify it.
 
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Old 01-07-10, 03:04 PM
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That sounds like a good middle ground - go over it once to hit the high spots and then give it a skim coat. Sure beats scraping the whole ceiling!

Thanks for the advice!

- Joe
 
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Old 01-21-10, 07:14 AM
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Just wanted to follow up and say that the skim-coated, scraped popcorn took knockdown quite nicely! Looks great! Thanks for the advice!

- Joe
 
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Old 02-05-10, 10:48 AM
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Originally Posted by joec2000
I've got a 1965 south FL home. I'm in the process of re-doing the kitchen and want a knockdown texture on the ceiling.
Just curious, what is a knockdown texture on a ceiling?

Can you post a pic or two of your finished product?

TIA,
Mike
 
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Old 02-05-10, 01:55 PM
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Sure... is there a way to post pics without signing up at those photo web sites?
 
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Old 02-05-10, 02:05 PM
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Not sure about that. I'm kind of new to the picture issue. I just saw your ceiling shots of the "popcorn", so that's why I asked.
 
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Old 02-05-10, 02:17 PM
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Actually, I put them those pics on my friend's web server. I probably shouldn't be doing that... I'll make another exception for ya.

Here it is still a little wet... it dries white.


It gets sprayed on with a hopper gun, allowed to dry for a little while, and then "knocked down" with very light pressure with a knife.

Here is the finished product:
 
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Old 02-05-10, 02:22 PM
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Excellent. Ceiling looks very nice.
I appreciate your efforts to make these available.

Thanks again.
 
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Old 02-05-10, 02:24 PM
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Not a problem - that's what these forums are for. I'll leave them up for a while in case anyone else is interested in seeing.

If anyone wants to see pics after I take them down, send me a message and I can email them to you.

- Joe
 
 

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