Once the room is prepped by covering everything in plastic, work on the ceiling is done in sections. For each section, the texture is wet down by misting it with water. The water loosens the popcorn so that it may be scraped off. It is possible that the water may loosen the tape at sheetrock seams as well, but this is easily handled by re-taping prior to "floating."
Floating is the process of applying thin layers of drywall compound ("mud") and sanding to achieve a smooth surface. The number of layers and amount of sanding is determined by the level of drywall finish required. If the ceiling is to be re-textured with a modern knockdown texture, "level 3" is sufficient. If the surface is to be left smooth, then "level 4" or even "level 5" is needed. For a good description of drywall finish levels, see "5 Levels of Drywall Finishes."
Once Tape & Float is completed and (optional) texture applied, the surface must be fully primed and then painted.
Removing ceiling popcorn typically involves wetting the texture to loosen it. If the ceiling has been reviously painted, the water will not soak in to loosen the texture.
We do not advise this for several reasons. First, dry scraping creates a lot more dust. Second, it leaves a significantly rougher surface that may require a lot of extra "floating" work to even out. Third, since the drywall compound used to float the surface is water-based, it may loosen up the remaining old texture and cause it to come off. Then you have a bigger mess to deal with and a more difficult job.
In order to protect walls from water, mud drips, primer, and paint, a curtain of plastic must be dropped from the wall/ceiling joint down. If the wall has wallpaper or a border at the top, we cannot guarantee that the tape required to hold up the plastic won't damage the paper when removed. Additionally, if the process of removing the popcorn loosens sheetrock tape at the wall/ceiling joint, then the wall will need to be disturbed to repair it.
Before the health hazards of inhaling asbestos dust were known, asbesto was considered and inert material with fire-retardant properties, so was commonly used as a filler material in popcorn ceiling texture mixes. In 1978, the use of asbestos was banned by the government, but supplies on hand were allowed to be used up. This is why we use 1980 as the cut-off point for determining whether we can work on your ceiling.
Simply having a pre-1980 popcorn ceiling does not automatically guarantee the presence of asbestos, but it is highly likely. Only a test performed by a credible laboratory will tell for sure.
It should be noted that the presence of asbestos in your ceiling does not make it a health hazard to your or your family. It is airborne asbestos particulates that are inhaled that are the health hazard. If a ceiling that contains asbestos is disturbed in a way that creates dust (cutting, scraping) then proper remediation steps must be followed.
First, find out for sure. A reputable lab can analyze a sample and give you a definitive answer.
If asbestos is present, and you still want to have the popcorn ceiling removed, you have two choices: A) Find a painting contractor who is certified in asbesto abatement and have them do he entire job, or B) Hire an asbestos-abatement company to handle the ceiling removal, and then hire us to do the tape & float, re-texture (if desired), and prime & paint.