In this single picture of a room with a newly installed drywall, you will see the basic layout of the sheets, fasteners, electrical box cutouts, joint compound, and where to sand. Through these steps, elements of this picture are broken down to show you the anatomy of a typical drywall project.
Horizontal vs. Vertical
When laying out drywall, you need to decide which direction to layout the rectangular-shaped sheets:
- Vertical: That is, four feet across and eight feet tall so that it completely reaches from floor to ceiling.
- Horizontal: That is, eight feet across and four feet tall.
Vertical placement is the classic way of laying out the drywall. But horizontal placement has its advantages, too. Some professional drywall installers deem horizontal placement to be a stronger form of installation.
In our pictured drywall example, note that not only is placement horizontal, but 10' x 4' sheets are used.
Position of Fasteners
With a cordless drill and coarse thread 1 5/8" drywall screws, you will drive a screw every eight inches along the entire perimeter of the drywall sheets.
You should also drive screws in the center of the sheets where they rest on studs. Studs typically run every 16" on-center. Note that in this example, the installer has run only a handful of screws into the studs, and has clustered them mainly in the center of each stud.
Where to Place Tape
Tape all drywall seams. Use fiberglass mesh tape or paper tape to tape flat seams. Fiberglass mesh is more expensive, but stronger. Paper tape is cheaper, but not as strong.
Inside and outside corners can be taped with regular paper tape. However, most drywall installers use the metal bead for inside and outside corners, or even metal-backed paper tape for inside corners.
Placement of Electrical Box Cutouts
There are two ways to mark and cut out electrical boxes (light switch boxes, electrical receptacles, etc.).
One way is to measure and cut the holes for the boxes ahead of time. This can be a frustrating process, though, as the hole is often misaligned.
A better way is to use a new item called Blindmark. Blindmark is a super-strong magnet that fits inside the box. After placement of the drywall, another part of the Blindmark device locates the hidden part. After you mark the spot with a pencil, it is easy to cut out the hole with a hand saw, jigsaw, or Dremel tool.
Apply joint compound to all taped areas and any depressions, scratches, dents, and screw holes.
First, smooth on the joint compound (also known as "mud") to the joints with a medium-sized taping knife. Then, feather out the mud with a large knife. After this first coat has dried and hardened, apply a second coat.
Smooth the joint compound over all drywall screw divots (holes), too.
Be judicious about applying joint compound: the more you apply, the more you have to sand down later.
Places to Sand
With a hand-held and pole-mounted drywall sanding tool, sand down all areas indicated in the picture.
Coarser grit sandpaper should be used in the first phase to bring down the rough areas. Avoid the temptation to use very coarse grit sandpaper; this will abrade the drywall paper surface.
Follow up with lighter grit sandpaper in the second sanding.
Small areas of the joint compound can be "sanded" with a wet sponge, called the "wet-sanding technique." This is a great way to help reduce drywall dust. Another way to reduce dust is to use a barrier system such as ZipWall.