Sanding Drywall Before Painting: Smooth Walls with the Right Grits

Freshly painted walls only look as good as the surface beneath the paint. If your drywall has rough spots, joint compound ridges, or sanding swirls, the final finish will highlight every flaw. The key to professional-looking walls is sanding drywall properly before painting, using the right grit sequence and tools.

Why Sanding Drywall Matters

Drywall finishing involves multiple coats of joint compound. Even skilled application leaves behind slight ridges, bumps, or tool marks. Sanding smooths these imperfections and blends the seams so they disappear under paint. Skipping or rushing this step results in uneven walls and visible lines once the paint dries.

Tools You’ll Need

• Drywall sanding pole or hand sander
• Wet/dry sandpaper sheets (medium to fine grit)
• Dust mask or respirator
• Shop vacuum or dust collection system
• Tack cloth or microfiber cloth

Best Sandpaper Grits for Drywall

• 120 grit: Initial smoothing of joint compound.
• 180 grit: Blending seams and feathering edges.
• 220 grit: Final surface prep for a paint-ready finish.

Step-by-Step: Sanding Drywall for Painting

1. Inspect the walls. Use a work light to highlight imperfections along seams and patches.
2. Start with 120 grit. Sand down ridges and bumps where joint compound was applied. Use a pole sander for ceilings and high walls, or a hand sander for smaller areas. Try 120 grit (25-pack) for efficient coverage.
3. Feather with 180 grit. Blend transitions between drywall and compound so seams disappear. Wrap sandpaper around a block for flat surfaces. A reliable option is 180 grit (50-pack), which balances durability and smoothness.
4. Refine with 220 grit. Finish with light passes to achieve a perfectly smooth surface ready for primer and paint. Stock up on 220 grit (100-pack) for large projects.
5. Control the dust. Connect a vacuum to your sander if possible. Otherwise, wipe surfaces frequently with a damp cloth to minimize airborne dust.
6. Final cleaning. Wipe the walls with a tack cloth or microfiber cloth to remove all fine dust before priming.

Special Cases

For skim-coated walls, stick to 220 grit to avoid cutting through thin layers of compound. On high-gloss finishes, wet sanding with fine grit helps prevent scratches that could show under glossy paint. If sanding plaster patches, start with 100 grit before moving into the drywall sequence.

Pro Tips

• Shine a bright light across the wall to reveal flaws before priming.
• Always sand lightly—pressing too hard can gouge drywall paper.
• Wet sanding reduces dust but takes longer to dry before painting.
• Prime with a drywall-specific primer to lock down dust and seal the surface.

Aftercare

• Clean tools immediately to prevent dust buildup.
• Store leftover sandpaper sheets flat to avoid curling.
• Dispose of drywall dust safely—avoid sweeping, as it becomes airborne easily.

FAQs

• Can I skip sanding if I use high-build primer? No—primer hides minor texture but won’t level ridges or seams.
• Is 100 grit too coarse for drywall? Yes, it may damage drywall paper. Start at 120 grit for safety.
• Do I need to sand between coats of joint compound? Yes, lightly sand each coat for the smoothest finish.

Watch & Learn

With the right grit sequence and technique, your drywall will be perfectly smooth and ready for paint. Explore more options in our medium grit collection and fine grit collection to complete your project.