What goes first ceiling or walls?

Consequently, which way do you hang drywall on a ceiling?

Installation starts in one corner of the ceiling with the length of the drywall panels running perpendicular to the direction of the ceiling joists. If the room is wider than the length of the panels, measure and cut additional panels so the panels meet on the center of a joist.

Subsequently, question is, do you stagger drywall on ceilings? It's not necessary to stagger seams on ceiling drywall. However, because these joints are relatively difficult to finish—and tend to be noticeable in the finished product—it's a good idea to stagger the drywall panels to make the joints less visible.

Herein, does it matter which way you hang drywall?

On commercial jobs, fire codes often require seams to fall on the entire length of the framing, so the drywall must be hung vertically. However, on residential jobs, the drywall on the walls is typically hung horizontally. For walls nine feet high or shorter, hanging the drywall horizontally has a number of benefits.

Should drywall touch the floor?

Drywall should definitely not touch concrete as moisture will wick (ie flow up the surface as in a candle/lamp wick) into the drywall and encourage mold growth. 3/8" should be sufficient - your prop up plan is not only appropriate, but a common technique used by drywallers.