If you have a drywall ceiling that is faded and old, you can either replace the drywall by tearing it away from the roof joists or you can cover it with plywood. A plywood ceiling will allow you to plaster or paint over it to give the ceiling a custom but well blended look, matching your home's interior. This is not a difficult task and requires only a modicum of experience with power tools to complete.
Set a stool under the drywall ceiling. Step on the stool and use a stud finder to find the joists the drywall is fastened to. Mark the location with a marker.
Hold the vapour barrier against the drywall ceiling and fasten it to the ceiling by driving stainless steel screws through the drywall and into the joists with a screw gun. This will keep moisture from warping the plywood should a leak occur.
Cut off excess vapour barrier along the edges of the ceiling with a utility knife.
Measure the dimensions of the ceiling with a tape measure. Write down the length and width of the ceiling. Plywood comes in 4-foot by 8-foot panels, so if the ceiling is 15 feet by 20 feet, or 300 square feet, you'll need 10 plywood panels.
Put on safety glasses and a dust mask. Measure and cut any plywood panels necessary to cover the entire drywall ceiling using a circular saw.
Hold the plywood panels against the vapour barrier covering the drywall ceiling. Drive stainless steel screws into the roof joists with a screw gun, spacing the screws about a foot apart. You now have a plywood ceiling covering the drywall.