You want a tight fit to the ceiling and if there is a gap at the bottom, the base trim will cover it.
If by top layer you mean the paper, then re-install drywall on that wall.
Almost anything you do WILL take off the top layer of paint and possibly drywall paper so be prepared to recover it with mud and sand it down.
shouldnt be a problem.if old drywall seal with a pigmented sealer first then retape and flush.after that treat surface as new.ie seal and double top coat.
White drywall is just normal everyday drywall.
Yes, you can use it....but what are you trying to do? The drywall primer is specifically designed to seal the drywall and make the surface uniform. You will not get any benefit from using it on top of a finish coat except for using it as a base coat for changing colors.
A drywall dimpler is a drill bit used to countersink a drywall screw to the proper depth without breaking the drywall paper.
Drywall has absolutely NO granite in it.
Drywall is VERY porous .
No, you cannot get cut by drywall
yes drywall is an insulator
The best sound proofing drywall plywood and adhesive solutions are somewhat a matter of debate. Some of the top selling solutions include sheet rock with SilentFX or QuietRock.
Yes, drywall is a light reflector.