Why Ceilings Are Different
Everything about ceiling installation is harder than walls. The sheets are heavy and awkward to position overhead. Gravity pulls against every fastener. Sagging is a constant concern.
Because of these challenges, ceiling drywall requires:
Closer screw spacing. Where walls might have screws every 12 inches, ceilings need them every 7-8 inches to resist the constant downward pull.
Thicker drywall. Half-inch drywall can sag between joists on ceilings. Most codes and good practice call for 5/8 inch on ceilings, especially if joists are 24 inches on center.
Better support during installation. You can lean a wall sheet in place while fastening. Ceiling sheets need to be held tight against joists.
All installation starts with the ceiling. The wall sheets get installed second and help support the ceiling sheet edges. Doing walls first means ceiling edges have nothing to rest on.
Using a Drywall Lift
A drywall lift is a wheeled device with a cradle that raises sheets to ceiling height using a hand crank or cable. It holds the sheet in position while you fasten, leaving both hands free.
Rental costs about $35-50 per day. You can buy a decent one for $200-300 if you have multiple projects planned. After that first disaster, I bought one and haven't regretted it.
Operating the Lift
Load the sheet onto the cradle face-down for ceilings. Most lifts have stops that hold the sheet at the right angle. Roll the lift into position roughly below where the sheet will go.
Crank the sheet up to the ceiling. As it rises, you may need to adjust the lift position to center the sheet where you want it. Once the sheet contacts the joists, crank a bit more to press it firmly.
Fasten the center first, then work outward. Keep pressure on the sheet with the lift until you have enough fasteners to hold it.
Without a Lift
If you absolutely must work without a lift, build T-braces from 2x4s. Make them slightly longer than floor to ceiling height. Two people position the sheet, then wedge T-braces underneath to hold it while fastening.
This works but is slow, tiring, and risky. Sheets can slide off the braces. People get hurt. Spend the money on a lift rental.
Sheet Orientation
Run ceiling sheets perpendicular to the joists. This means each sheet crosses multiple joists, giving you more fastening points and stronger attachment.
If you run sheets parallel to joists, you're relying on a single joist to support most of each sheet's weight. The edges fall between joists with nothing to fasten to. It's a recipe for sagging and cracking.
Stagger the end joints. Just like walls, you don't want seams lining up in a continuous line across the ceiling. Start alternating rows with different length pieces.
Keep the factory edges toward the center of the room where possible. Factory edges are tapered and designed for taping. Cut edges are square and require more buildup to finish flat.
Fastening Pattern
Ceiling screws need to be closer together than wall screws. The standard is 7-8 inches apart along each joist.
Start in the center of the sheet and work outward. This keeps the sheet tight to the joists as you work. Starting at edges can cause the center to bulge.
Keep screws at least 3/8 inch from sheet edges. Closer than that risks breaking out the edge.
At the perimeter, the wall sheets will provide additional support once installed. But the field of the ceiling is supported only by your screws into joists. Don't skimp.
I use more screws on ceilings than most guides suggest. The cost of extra screws is trivial compared to the cost of a sagging ceiling later.
Dealing with Lighting
Recessed lights, ceiling fans, and hanging fixtures all need cutouts in the drywall. Mark and cut these before lifting the sheet into position.
For recessed can lights, measure from reference points to the center of each can. Transfer to the sheet and cut circles slightly larger than the cans. Most cans have clips that grab the drywall edge, so precision matters.
Ceiling boxes for fixtures should be measured the same way you measure wall boxes. Cut holes to expose the box, leaving room for the fixture canopy to cover the edges.
Check your cutouts before lifting. Hold the sheet in approximate position and verify the holes line up with the fixtures. Adjusting a sheet that's already fastened is much harder than adjusting before it goes up.
Avoiding Sag
Ceiling sag happens over time when drywall stretches between joists. It's ugly and hard to fix without replacing the affected sheets.
Use 5/8 inch drywall. It's stiffer than 1/2 inch and resists sag better. Most building codes require it for ceilings anyway.
Maintain proper screw spacing. More fasteners mean less distance for the drywall to span unsupported.
Consider glue. Construction adhesive on the joists before hanging creates a bond that supplements the screws. Some pros always use it, others never do. I use it on ceilings where I'm worried about sag, like over large rooms with 24-inch joist spacing.
Don't over-wet when finishing. Excessive water in joint compound can temporarily soften the drywall. If you're applying thick coats on a ceiling, the weight of wet mud can contribute to sag. Use thinner coats.
Finishing Ceiling Joints
Taping and mudding a ceiling is the same technique as walls but more tiring. Gravity pulls wet compound off your knife and onto your face.
Work in sections. Do what you can comfortably reach, then move your ladder or scaffold.
Use stilts if you're comfortable with them. Many pros do ceiling work on drywall stilts, which keeps them at a comfortable working height without constant ladder moving. I've never been coordinated enough for stilts, so I use a scaffold.
Light the ceiling for finishing. Ceiling flaws hide in normal lighting but show up in raking light. Set up work lights that hit the ceiling at low angles to reveal imperfections while you can still fix them.