Sandpaper for Painting Walls: 5 Expert Tips: Practical sanding advice from a designer who’s sanded more walls than wallpaper rolls

I once sanded a wall so enthusiastically I sanded a corner down to the drywall paper — the homeowner called it my “minimalist reveal.” That laughable mistake taught me to slow down and pick grit like a chef picks knives. If you’re prepping paint in a small room, learning to visualize the end result helps avoid over-sanding and extra patchwork; I often tell clients to visualize the layout first so the painting sequence makes sense.

1. Start coarse, finish fine: grit progression

I usually begin with 80–100 grit only if there are heavy ridges or old texture to remove, then move to 120–150 for general smoothing, and finish with 180–220 before priming. The upside is speed and a truly smooth finish; the downside is you must watch pressure — too hard and you create low spots. Budget tip: buy a mixed-pack of grits so you can experiment without overspending.

2. Use a sanding block or pole sander for flat walls

Hand-sanding with a block keeps pressure even and prevents accidental gouges I once made with a freehand sponge — true story. For ceilings or tall walls, a pole sander saves your shoulders but can be less precise around edges. If you’re on a shoestring, wrap sandpaper around a wooden block and add a cloth for grip; it’s old-school but works.

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3. Target imperfections, don’t overwork the surface

Fill dents and nail holes first, then sand those spots smooth with 120–150 grit; I find this approach keeps the paint layer consistent. Over-sanding the whole wall to “match” a spot wastes time and drywall paper — instead, feather the repair edges so the paint covers evenly and you can test different layouts of repair and paint zones in your head. Small challenge: feathering takes practice, but it’s the trick pros use to hide repairs.

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4. Control dust like a pro

Dust is the enemy of a smooth finish. I use a shop vacuum with a sanding attachment or tack cloths after vacuuming; in small spaces, also seal vents and open a window. The benefit is cleaner paint adhesion and less sanding later, but prep takes extra minutes — worth it for a flawless finish. Pro tip: damp-wipe after vacuuming to capture fine particles before priming.

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5. Final sanding and visual checks before primer

Do a last pass with 180–220 grit, then step back with a bright light to spot low spots or halos. I often take a quick photo with my phone and view it in grayscale to catch subtle flaws — and if you want to see a 3D mockup of your space, that perspective helps plan the final paint sequence. The advantage is fewer touch-ups after the first coat; the tiny challenge is resisting the urge to keep sanding — at some point you need to prime.

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FAQ

Q1: What sandpaper grit is best for painting walls?

A: For most wall prep start with 120–150 grit for smoothing imperfections and finish with 180–220 grit before priming. Coarser grits (80–100) are for heavy removal only.

Q2: Can I sand painted walls without a sander?

A: Yes — use a sanding block and appropriate grit. Hand sanding gives control but takes longer, especially for large areas.

Q3: How do I avoid swirl marks?

A: Use even pressure with a sanding block and follow a grit progression — don’t skip straight from very coarse to very fine. Finish with light, uniform strokes to minimize visible sanding lines.

Q4: Is dust from sanding walls hazardous?

A: It can be, especially if lead paint is present in older homes. The EPA advises testing for lead paint before sanding if your home was built before 1978 (see https://www.epa.gov/lead). Use proper PPE and containment if lead is detected.

Q5: Should I wet-sand drywall?

A: Drywalls are typically dry-sanded, but for very fine finishing some pros use a slightly damp sponge for skim coats. Wet-sanding drywall paper can damage the surface if done incorrectly, so proceed cautiously.

Q6: How do I clean walls after sanding?

A: Vacuum with a brush attachment, wipe with a tack cloth, then follow with a damp microfiber cloth and allow to fully dry before priming. Clean surfaces help paint adhere better and reduce flaws.

Q7: Can I repaint over glossy paint without sanding?

A: You should scuff-sand glossy surfaces with 120–150 grit to provide mechanical keying; skipping this step risks poor adhesion and peeling. For high-gloss to matte transitions, thorough sanding is essential.

Q8: How long should I wait between sanding and priming?

A: After cleaning, wait until the wall is completely dry — typically 30–60 minutes depending on humidity — then apply primer. Proper dryness ensures the primer bonds well and prevents trapped moisture issues.

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