Encyclopedia

of Home Improvements

*Drywall*

Finishing Seams in thin even coats

Start taping perimeter seams by laying down a thin bed of compound along the seam using a 4-in. wide knife.

Press paper tape into the joint, and then wipe away the excess. When the tape is dry, apply a second coat of compound with a 6-in. knife. Let this coat dry and apply a coat on top of it.

When this is dry, sand it lightly with the fine side of a dual-grit sanding sponge. Apply one or two more coats on top of this using the 6-in. knife. Joints that run parallel to the drywall sheet's long axis should be coated to about 12 in. wide, but those that run perpendicular to the long axis (on the ends of the sheets) need to be coated to about twice that because drywall is not tapered at the ends as it is on the edges. This makes it harder to hide the end joints, so you have to cover them with a very wide seam that has an extremely shallow taper.

Your first pass on joints may look a little rough. On subsequent passes, you can eliminate ridges and other imperfections by reducing the compound on the knife to just a small glob in the blade's center. There are other tricks. I like a fairly stiff knife that I put a slight bend in the blade so that its trailing edge rides slightly above the compound as you pull the knife down the joint. And if you find the knife is leaving marks as it smoothes the compound take the last stroke in the opposite direction of the one before. If the first stroke was right to left, pull the last stroke left to right.

Dealing with Wiring and Outlets

Electrical cables and pipes that run through wall and ceiling framing need protection because they can be pierced by a drywall nail, creating a fire hazard or a leak. The solution is simple. Install self-gripping steel protection plates. Simply hammer them onto the studs.

To mark cutouts for electrical boxes, measure to the outside of the box using the edge of the adjacent drywall sheet as a reference point. Transfer the measurements to the panel using the drywall square, (photo5) and cut on the outside of the pencil lines with a drywall saw. Now nail the drywall to the stud. If the cutout for the box isn't perfectly positioned and it needs to be enlarged, pen it up slightly with a drywall rasp.

Working Inside and Outside Corners

Start work on the outside corners by cutting metal corner bead to length with utility snips. Then lightly hold it in position. Check that the bead is properly aligned when viewed from both sides of the corner, and then nail one face completely before nailing the second side.

Space the nails 12 to 16 inc. apart. For inside corners, spread compound on both surfaces with a 4-in. wide drywall knife. Fold paper drywall tape in the center and press it into the corner. Squeegee away the excess compound with an inside corner knife.

Hanging Drywall From the Top Down

Hang drywall on the ceiling first, then the walls. Check the ceiling for bowed joists using a 4-ft. level. Irregularities less than 1/8-or1/16-in.-thick cardboard.

Use the longest sheet available to cover the surface. If the ceiling is 12 ft. long, there's no sense in using an 8-ft. sheet. You want as few seams to tape as possible.

With a helper, lift the sheet against the ceiling and hold it across the framing using a T-brace built ¾ in. shorter than the floor-to-ceiling height. Use a drywall hatchet or hammer and bang in some ring-shank drywall nails, dimpling the drywall paper above each. Place a nail at each joist along the panel's edge, and space them at about 16-in. intervals in the panel's center. To cut a sheet, use a drywall square to guide the utility knife and score across the panel's face. Snap on the score line. Nick the backing paper from the front, and then score all the way through from the back.

Next, move to the walls. Apply a bead of construction adhesive on each stud to reduce the chance that nailheads could break through the drywall finish as the framing lumber dries. Lift the sheet to the top of the wall and nail it in place.

The Basics - All About Drywall

• Building codes specify thickness and type of drywall, but you can use the following as a rule of thumb. Always check your local code.
• Standard ¼-in. - Covers cracks and is easy to bend around radiuses.
• Standard ½-in. - Covers walls and ceilings framed on 16-in. centers.
• Standard 5/8-in. - Covers walls and ceilings framed on 24-in. centers.
• Fire-resistant 5/8-in. - Covers walls and ceilings in an attached garage or in the room above.
• Water-resistant ½-in. - Serves as a tile backer on bathroom walls.
• Water-resistant 5/8-in. - Serves as a tile backer on bathroom ceilings.
  
  
  
  

Back to Topics Page

Contact