How to Apply Drywall Joint Tape

Most do-it-yourself enthusiasts are fairly confident in their ability to install drywall sheets. Where they start to have misgivings is when it comes to taping and finishing the seams and edges. Applying joint tape and finishing your drywall project won't be a major hassle if you give the project the right amount of time, use the right tools and follow the proper procedures.

Things You'll Need

• Bucket of water
• Premixed drywall compound
• Metal corner beads
• Pan to hold the mud
• Corner tool (for inside corners)
• 4-, 6- and 10-inch drywall knives
• Sanding block
• 200-grit sandpaper
• Drywall tape (paper or fiberglass mesh)

Instructions

Choose Your Drywall Tape

1. Decide whether you want to use paper drywall tape or sticky-back fiberglass mesh tape. Professionals use paper tape, but many amateurs prefer the fiberglass mesh tape because it sticks by itself. The down side to the mesh tape is it's thicker than the paper tape and the mesh can get caught on the drywall knife on the first coat. The following steps apply to paper tape.

Taping Walls

1. Cut the pieces of tape for the seams to the proper length and lay them near where they'll be used.

2. Use your 4-inch drywall knife to spread a layer of premixed drywall compound (mud) along the drywall seam. The mud should cover at least the width of the tape.

3. Wet your 4-inch knife in a bucket of water and then center the tape on the joint. While holding the tape at the top, run your 4-inch knife (held at a 45-degree angle) along the length of tape, pushing it down into the mud. Apply enough pressure to force the tape well down into the mud and force excess mud out around the edges. Scrape away the excess mud and allow the mud to dry overnight.

4. The next day, use your drywall knife to scrape away any dried mud that is creating ridges or bumps along the seam. You may need to use two hands to get rid of some of them, but it's important that you end up with an even surface.

5. Wet your 10-inch knife and apply a second coat of mud about 6 inches wide that covers your first layer. Hold the knife perpendicular to the seam and scrape down the seam, removing any excess mud from the edges.

6. Again let the seam dry overnight. Dry scrape the wall to remove any bumps or ridges and then wet your 10-inch knife and apply the third coat, but this time cover a wider area-8 to 10 inches wide. Allow it to dry.

7. Scrape away any ridges when the mud has dried and then lightly sand the edges using 200-grit sandpaper.

8. Vacuum or sweep up the dust and apply a primer in preparation for painting the walls.

Outside Corners

1. Install metal corner beads (available at home stores) on the outside corners. Measure and cut them to length using tin snips. Use nails or drywall screws about 8 to 10 inches apart, and be sure the heads are below the metal edge. Check that no heads are protruding by running a drywall knife down the length of the corner bead bridging the corner bead and the wall.

2. Apply joint compound (using your 6-inch knife) along the length of the corner bead. Hold one side of the knife on the bead and the other on the wall. Do the same on the other side and allow the joint compound to dry overnight.

3. Use your knife to scrape the edges smooth and then wet your 10-inch knife and apply a second coat of mud. Spread it about 8 inches wide and allow it to dry.

4. Apply a third coat using the same process (this time go about 10 inches wide on the wall side) and then lightly sand the area prior to painting.

Inside Corners

1. Apply a layer of mud to both sides of the corner.

2. Fold your tape in half and hold it in the corner.

3. Use your cornering tool and run it along the length of the seam to embed the tape into the mud, forcing some out around the edges.

4. Apply some mud to the walls and some to your corner tool. Using a smooth stroke, run the corner tool down the length of the seam, spreading the layer of mud. Feather out the edges using your 6-inch knife.

5. Apply subsequent coats (allowing them to dry between coats) using your 6-inch knife and spreading the mud wider with each coat until you end up about 8 inches out of the corner on each side.

6. Lightly sand the edges and prime the wall.

Tips & Warnings

• Drywall mud tends to thicken quickly when exposed to air. Keep it moist and slightly thinned out so it will spread easily.

• Rusty or dirty tools will not only make your job harder, but can stain your walls. Clean and dry your knives after each use.

• Don't try to do your drywall taping with only one knife. The pros use more than one-sized knife and you should as well.

• Even knowing the proper techniques, getting professional-looking walls requires patience. Don't rush the job and don't skip a step or your final results will look anything but professional.