8 Steps for Perfect Outside Drywall Corners

Outside corners tend to take more of a beating, so it is definitely a good idea to reinforce them with a metal corner bead. The bead is nailed to the outside corner, and then joint compound is applied. Before tackling this project, keep in mind that you should allow a day for drying for each coat of joint compound. So pick a time when you won't mind having a wall "under construction" for a few days.

Ready to get started? This guide outlines the systems for applying drywall, cutting and securing the corner bead and applying drywall compound.

1. Start with a corner that's straight and secure

Check the straightness of the framing before hanging the drywall–then you may assemble the corner so there are no overhanging edges. Rule of thumb: Cut your first board flush with the edge of the corner stud; cut the second board so that it overlaps halfway onto the first board. Secure the edges by placing screws no more than 12 in. apart.

2. The adhesive coat must be thin

To allow the bead to seat tightly to the wall, add enough water so that the compound becomes the consistency of thick pancake batter. Next, spread a generous amount of compound in a 2-in.-wide strip on each side of the corner. Hold the knife so that it's almost flat, and apply light pressure to ensure a consistent layer of compound.

3. Use finger pressure

Place the bead in the joint compound and push it tight it the ceiling. Then, rub your thumb and finger along the paper edges–lightly applying pressure.

4. Gently wipe the edges

Use your taping knife as a straightedge to check a few spots on either side of the bead to ensure that the nose stands proud to the wallboard. If not, coax the bead to one side or the other with your fingertips. Once you have the bead correctly positioned, hold your knife at a 45-degree angle and gently wipe each– using your index finger to gently flex the blade.

5. Mix the mud between coats

Even if your bucket of joint compound doesn't need added water, it still needs to be thoroughly stirred before you use it. Mixing the joint compound ensures a uniform consistency throughout the bucket. Mixing also makes the compound easier to spread.

Professionals typically use a speed mixer with a slow-speed drill to mix joint compound. But, a hand-operated "mud masher" is much less expensive, and can be just as effective.

6. Smooth the first coat

Load up an 8-in. taping knife with compound (mixed with little to no water– will minimize the shrinkage). Wipe the corners of the taping knife on the edge of your joint compound pan to prevent drips. Next, spread compound over one side of the corner, ensuring that the nose of the bead is fully covered. The smoothing process requires three easy steps:

• Hold the knife at an angle and screed the compound between the inner wall surface and the bead. Make a long, smooth swipe from the top, and one from the bottom. Don't stress about lap marks–we will get to those later!
• Hold the knife at a 45-degree angle and apply pressure to the inner edge to feather the inside edge of the compound– the outer edge of the knife should not touch the mud!
• Repeat the first step, but utilize your forefinger to apply slight pressure. After your final pass, the nose of the bead should be just as visible as the edge of a concrete form.

7. Fill the gaps with your final coat

After waiting for the first coat to dry (should take about a day), sand the corner lightly with 100- to 150-grit paper to get rid of the lap marks and other high spots. Your final coat of joint compound should be slightly thinner than the previous one– but thicker than the adhesive coat. Apply the compound with a 10-in. knife.

8. Skim and sand

Hold the taping knife at a 45-degree angle and apply light, evenly distributed pressure. Once the coat is dry, sand the corner lightly using extra-fine (150-220 grit) sandpaper. Congrats, you're done!

Perfect your outside drywall corners with help from Al's

Al’s Taping Tools has been providing contractors with the most extensive selection of professional-quality tools, parts, and accessories since 1985. Our experts are here to help you find easy ways to save time and money on your next project. Shop our products today to give yourself an advantage on any job site.