How to Taper Drywall Edges Perfectly

An unfinished room with hung drywall
Perry Mastrovito / Design Pics / Getty Images

Hanging and aligning drywall perfectly can be tough. Whenever possible, it is preferable to align the two tapered (or angled) edges of adjoining sheets of drywall. But when you have two straight edges that have no built-in taper, it can be difficult to match the two edges and taper them with drywall tape and drywall compound. But with a little practice, you can taper two butt edges just like a professional drywall technician.

How Do Drywall Tapers Work?

When you look at a piece of drywall closely and feel it with your hand, you will notice that on each of the long edges there is a taper. When two of these tapered edges meet, they form a flat V-shaped void that is easily filled in with joint compound or mud and makes the join invisible.

Unfortunately, it is not always possible to join a tapered edge to another tapered edge. Sometimes, two straight factory edges meet. Or other times, cuts will create straight edges. Then, adjoining butt edges is your next best option.

Paper tape is adhered to the seam with drywall compound and allowed to dry. Next, the drywall compound is tapered over that seam to form a micro-thin ridge that covers up the seam.

Project Metrics

  • Working Time: 15 minutes per 8 linear feet
  • Total Time: 2 hours
  • Skill Level: Intermediate
  • Material Cost: $10 to $25

What You Will Need

Equipment/Tools

  • Utility knife
  • Wide drywall knife, 12-inch
  • Narrow drywall knife, 6-inch
  • Drywall sander and pole

Materials

  • Paper drywall tape
  • Drywall compound (mud)
  • Drywall sanding screen

Instructions

Remove Stray Paper

With your sharp utility knife, run it at a 45-degree angle down the entire length of each butt edge that will meet. The purpose is not to try to create your own tapered edge as this is difficult to do by hand. Instead, remove stray paper sticking out from the drywall. When two butt edges are forced against each other, the paper has a tendency to ripple and buckle, creating an unsightly ridge. By slicing off about 1/8-inch of this paper, you prevent the two butt edges from creating this ridge.

Stick the Tape to the Drywall

Cut off the correct length of drywall tape with the utility knife. With the broad drywall knife, apply a thin layer of drywall compound to the seam. Without delay, apply the drywall tape to the seam. Press the tape into the compound so that it sticks. Remove any bubbles or folds that may form under the tape.

Let It Dry

The tape should thoroughly dry and stick to the seam before you undertake subsequent steps. If not, the tape may slide around and become difficult to fix.

Apply Drywall Compound

After the tape has dried to the seam, use the 6-inch drywall knife to apply a narrow band of drywall compound over the tape. This band of the compound should extend only 1 to 2 inches beyond the tape. Keep the compound low, working out any peaks and bubbles. Quickly scrape off any drywall compound that accidentally ends up beyond the seam.

Light Spot-Sand (Optional)

Excessive sanding will abrade the paper covering on the drywall. So, this initial sanding is only designed to remove any peaks or bumps that may have developed earlier and which were allowed to dry. Do not sand the entire seam. Sand only the problem area, and apply only light pressure.

Apply Drywall Compound

Use the broad, 12-inch drywall knife to apply drywall compound over the seam. Extend beyond your earlier work. Feather out drywall compound with the knife so that it seamlessly merges into the adjoining drywall.

Sand the Drywall

After the compound has dried, sand the seam. The goal is not to bring the seam down flat; there will always be a slight ridge so that it can cover up the tape. Instead, aim for creating a smooth transition from the seam to the drywall on either side.

Tips For Tapering Drywall

  • Apply only as much drywall compound as is needed. The more compound you apply, the more you will need to sand off later on.
  • Use dust-control drywall compound for a cleaner work site.
  • Transfer the drywall compound to a mud pan. This long, narrow pan is designed to be used with drywall knives.

When to Call a Professional

Butting up and creating a smooth join between two drywall sheets often can be more of an art than a craft. Many do-it-yourselfers find that they cannot master this trick—understandably so. If you find that you cannot do this, call in a drywall company to complete the work for you.