Condo popcorn ceiling removal

flyingnurse wrote: ↑ 1 - there is concrete under the popcorn, I am going to remove the popcorn down to the concrete. I do not see anything between the popcorn and concrete. Is this right?

2 - once I remove all the popcorn, what prep is needed to the concrete? Is there a compound I need to apply first in order to get the smooth surface, and then I paint it.

flyingnurse wrote: ↑ 1 - What test patch am I doing? Are you referring to a small section that I skim coat? What am I looking for?

2 - Maybe a dumb question, I am looking at tutorials on skim coating, I highly doubt I will get it as smooth as the professionals, am I able to sand out the imperfections?

3 - How do I assess if my concrete is flat? Use a leveler?

SubjectivelyObjective wrote: ↑ 1 - Basically before you get set up to do a bunch of work... After you've scraped everything, just take a bit of mud and put it on a small area, like 2' x 2' or something. Just to make sure the concrete sealer is still doing its job, and it dries properly, etc.

2 - Even the pros sand after the fact. You are going to have lift offs in a number of locations no matter how good your are. So yes, sanding will be needed regardless after you skim. Again, a skimming blade thats 36" or maybe 24" if you don't want to go super wide is really valuable. It will save your shoulders a ton compared to troweling it on or using a smaller knife.

3 - Just take a straight edge, 48" level, 78" level, whatever. It probably won't be as wavy as a normal ceiling, but there could be some low/high spots. Good to know where they are ahead of time. How good your ceiling needs to be done mostly depends on lighting. If all your lighting is down lighting you can get away with lots of sins and no one will see them. If you have cross lighting across the ceiling you're going to need to do closer to a legit level 5 job.

My usual protocol for a ceiling is:

Sand off popcorn > Skim coat the whole thing with a roller and 36" blade > Let dry for 24 hours > A quick sanding > Skim coat #2 with roller and 36" blade > wait 24 hours > Come back for final sanding, touch up any small things with a trowel and quick dry mud, and a bit more sanding.

After that you're all good for priming.

Cheapo-Findo wrote: ↑ Ain't the concrete popcorn is to isolate sound and shouldn't be a concern if buildings were built not long ago?

kenchau wrote: ↑ OP what about the bare exposed concrete look?

Some condos leave the ceiling concrete exposed as part of the look.

Although, I suppose it isn't clean like bare concrete since popcorn was previously on it.

flyingnurse wrote: ↑ Thank you for the wonderful explanation, I will begin this endeavor. Do you apply a chemical to clean the concrete before you apply the 1st coat of slim coat?

SubjectivelyObjective wrote: ↑ Nope, I never use any chemical or anything on the ceiling before hand. I use a planex to take the popcorn off and then when its basically flat I'll start my first skim coat from there. I would proceed with the assumption that the sealer and a bit is still on there after you've removed it and everything is fine. Then if you do a test patch and it goes poorly, evaluate from there.

Assuming you don't have a drywall sander attached to a vac, I would recommend vacuuming or wiping down the whole ceiling to get rid of any fines or little bits up there that may cause you an issue later.

hierophant wrote: ↑ OP I was thinking of doing the main floor (kitchen was already done) so roughly 400sft myself next month. Let me know how it goes.

SubjectivelyObjective wrote: ↑ Nope, I never use any chemical or anything on the ceiling before hand. I use a planex to take the popcorn off and then when its basically flat I'll start my first skim coat from there. I would proceed with the assumption that the sealer and a bit is still on there after you've removed it and everything is fine. Then if you do a test patch and it goes poorly, evaluate from there.

Assuming you don't have a drywall sander attached to a vac, I would recommend vacuuming or wiping down the whole ceiling to get rid of any fines or little bits up there that may cause you an issue later.

flyingnurse wrote: ↑ So I did the first step and that was to remove the old popcorn from the ceiling. On a couple spots I hit some netting material and I imagine that is used to bond the popcorn ceiling and the cement.

My next step is to sand this down and then get rid of the dust before I apply the 1st skim coating.

What grit sandpaper do I use?

SubjectivelyObjective wrote: ↑ For removal of painted stuff I use 24-40 grit, for removal of non painted I use 80 grit, and for finish sanding I usually use 180 grit. Seeing as you're doing it by hand? I would opt for a lower grit for removal.

Also, its hard to tell based on those pics, but if you got all the popcorn off and its somewhat flat-ish, you might be able to start from there.

Another tip, is that cross lighting helps a ton. With a light across the ceiling you will see all the imperfections and can make it perfect, so you'll never see anything under normal conditions. I use the dewalt tripod light.

flyingnurse wrote: ↑ Thanks, just to clarify, the white parts of the ceiling are the remnants of the popcorn ceiling. Some areas I have hit bare concrete while other areas is the remnants. Are you suggesting that I sand down the white remnants areas until I get concrete? Is the white popcorn remnants the "painted stuff"? What if I sand the entire ceiling with 80 grit?

SubjectivelyObjective wrote: ↑ You should be fine sanding with 80 grit, most of the painted stuff probably came off in the first layer. This said, you're just removing, so lower grits probably make your job faster.

In terms of what to sand too, you don't need to reach concrete. Just as long as you get a flatish ceiling, that isn't too wavy or doesnt has massive high spots to fill, you can start from there.