How to Sand Drywall Corners Without Damaging Edges (150–400 Grit)

Drywall corners are one of the trickiest areas to sand. Too much pressure can damage the paper tape, while uneven sanding can leave ridges that show under paint. With the right grit sequence and technique, you can achieve crisp, smooth corners ready for primer and paint.

Why Sanding Corners Matters

Joints and corners often have excess joint compound buildup. Sanding ensures the surface blends seamlessly with adjacent walls, preventing visible lines or bumps after painting.

Tools You’ll Need

• Corner sanding sponge or angled sanding tool
• Dust mask and safety goggles
• Tack cloth or vacuum with brush attachment
• Wet/dry sandpaper sheets (150–400 grit)

Recommended Grit Sequence

• 150 grit: Initial smoothing of rough compound buildup.
• 220 grit: General sanding to blend corners with wall surfaces.
• 320–400 grit: Final smoothing before primer and paint.

Step-by-Step Process

1. Inspect the corner. Shine a work light across the surface to identify ridges or uneven spots.
2. Start with 150 grit. Use 150 grit (25-pack) sheets or sponges to knock down heavy compound buildup.
3. Smooth with 220 grit. Refine surfaces using 220 grit (50-pack) sheets for blending edges into surrounding drywall.
4. Finish with 320–400 grit. Lightly sand with 400 grit (10-pack) wet/dry sheets for a flawless finish ready for primer.
5. Clean the area. Vacuum dust, then wipe with a tack cloth to remove fine residue.
6. Prime and paint. Apply drywall primer to seal the surface before painting.

Special Cases

For inside corners, sanding sponges provide better control than sheets. For outside corners with metal bead, avoid sanding too aggressively to prevent exposing bare metal.

Pro Tips

• Use light pressure—corners are easy to oversand.
• Always keep sanding strokes short and controlled.
• Check progress frequently under angled light.
• Wet sanding with fine grits reduces dust and helps achieve smoother results.

Aftercare

• Prime corners thoroughly to seal sanded areas.
• Apply two finish coats of paint for durability.
• Inspect under bright light before painting to catch imperfections.

FAQs

• Can I use power sanders on drywall corners? Not recommended—hand sanding provides more control.
• Do I need to sand after every coat of compound? Yes, light sanding between coats ensures smooth layering.
• What if I sand through the tape? Apply a thin skim coat of compound, let dry, and resand gently.

Watch & Learn

Perfect drywall corners require patience and the right tools. Stock up on medium grits, fine sheets, and super fine sandpapers to make every wall project look flawless.