Introduction
Drywall corners are one of the most challenging parts of finishing a wall. While flat seams can be forgiving, corners require precision, patience, and the right technique. If they aren’t done properly, they can look bulky, uneven, or prone to cracking.
Many homeowners assume that the hard part is over once the drywall is hung. But taping and finishing the corners can be where the real frustration begins. Common mistakes like using too much joint compound, failing to embed the tape correctly, or sanding too aggressively can make even a well-hung drywall job look amateurish.
The good news is that getting perfectly smooth drywall corners isn’t as difficult as it seems — it just takes the right approach. Whether working with inside or outside corners, this step-by-step method will help you achieve flawless, professional-looking results.
Understanding the Two Types of Drywall Corners
Before starting the process, it’s important to understand the difference between the two types of corners and the challenges each presents.
Inside Corners
- Found where two drywall panels meet at an inward angle.
- Prone to cracking, visible tape lines, or excess mud buildup if not done correctly.
Outside Corners
- The exposed edge where two drywall panels meet to form an outward angle.
- They chip, dent, or develop uneven mud buildup if not properly reinforced.
Each type requires a different technique and the right materials to ensure a smooth, durable finish.
How to Get Perfect Inside Corners
Step 1: Apply the First Coat of Joint Compound
- Using a 6-inch taping knife, apply a thin layer of joint compound along both sides of the corner.
- This acts as a bonding layer for the tape and prevents air pockets.
Step 2: Apply the Drywall Tape
- Use paper tape for inside corners, as it’s stronger and resists cracking.
- Fold the tape along its center crease and press it firmly into the wet compound.
- Use a drywall knife to smooth the tape, removing excess mud and ensuring a strong bond.
Step 3: Apply the Second and Third Coats
- Once the first coat is dry, apply a second layer of joint compound with a corner trowel or a 10-inch knife.
- Feather the edges so the transition between the mudded area and the drywall is seamless.
- After drying, apply a third coat, widening the feathered edge even more to create an invisible transition.
Step 4: Sand Lightly and Prime
- Use fine-grit sandpaper (120–150 grit) to smooth ridges or imperfections.
- Avoid over-sanding, which can weaken the corner and expose the tape.
- Always apply a primer before painting to ensure even paint absorption.
One common mistake I see is applying too much mud in one coat. This makes sanding a nightmare and often leads to cracking once dry. Taking the time to apply thin, even coats ensures a smoother, stronger finish.
How to Get Perfect Outside Corners
Step 1: Install the Corner Bead
- Metal or vinyl corner beads reinforce the edge and ensure a straight, durable corner.
- Attach it using drywall screws or staples every 6 inches along both sides.
Step 2: Apply the First Coat of Mud
- Using a 6-inch taping knife, apply a thin layer of joint compound over the corner bead.
- Smooth it evenly along both sides, covering the bead while keeping the profile sharp.
Step 3: Apply the Second and Third Coats
- Once the first coat is dry, switch to a 10-inch knife and apply a second coat.
- Feather the edges wider to create a smooth transition.
- The third coat should be more expansive, ensuring a seamless, almost invisible edge.
Step 4: Sand and Check for Imperfections
- Use a sanding sponge or sanding pole for the final smoothing.
- Hold a work light at an angle to catch any remaining imperfections before priming and painting.
A common issue with outside corners is applying too much pressure when sanding, which can expose the metal or vinyl corner bead. Light, even sanding, is key to maintaining a crisp edge.
Pro Tips for Flawless Drywall Corners
- Use Thin, Even Coats — Thick layers of mud take longer to dry and often lead to uneven results.
- Let Each Coat Dry Completely — Rushing through coats increases the risk of cracking.
- Feather the Edges — Always extend the mud beyond the previous coat for a seamless blend.
- Use a Corner Trowel for Inside Corners — This helps create an even application with fewer tool marks.
- Prime Before Painting — Drywall and joint compound absorb paint differently, so a primer is essential for uniform coverage.
One of the most overlooked steps in drywall finishing is checking your work under proper lighting. Shadows can hide imperfections that become painfully obvious once the final coat of paint is applied. Taking a moment to inspect the corners before finishing saves time and frustration.
Conclusion: Smooth Drywall Corners Made Easy
Perfect drywall corners aren’t just about applying mud and tape — they require patience, the right tools, and a proper step-by-step approach. By using the correct materials, feathering out each coat, and taking time to sand carefully, you can achieve professional-quality corners every time.
Key Takeaways:
- Use paper tape for inside corners and corner bead for outside corners.
- Apply thin, even layers of joint compound, allowing each to dry thoroughly.
- Sand lightly to avoid over-sanding and weakening the finish.
- Prime before painting for a flawless final look.
If you’ve ever been frustrated by rough, uneven corners, following this method will make all the difference. Your drywall corners will look as smooth and seamless as a professional job with patience and the right approach.
Need Professional Help?
If you’re working on a drywall project and want perfectly smooth, seamless corners without the hassle, contact us today. We specialize in expert drywall finishing, repairs, and flawless installations. Let us take the stress out of your project and deliver lasting results.