Sand Drywall Smooth
Achieve a flawless, professional finish by properly sanding drywall joints and compound. This critical step ensures your attic walls are ready for priming and painting.
Why Proper Sanding Matters
Sanding is what transforms rough drywall joints into invisible seams. Even perfectly applied joint compound will have ridges, tool marks, and texture that must be removed. Paint and primer actually highlight imperfections rather than hide them, so thorough sanding is essential for a professional finish. In attic conversions, the angled ceilings and knee walls create unique challenges, but with the right technique and patience, you can achieve walls that look like they were done by a pro.
Tools & Materials Needed
Step-by-Step Sanding Guide
Prepare the Work Area
Attic spaces require extra preparation due to limited ventilation:
- •Seal the attic access opening with plastic sheeting and tape
- •Cover any HVAC vents or returns with plastic
- •Set up a box fan pointing out a window for ventilation
- •Wear an N95 respirator and safety glasses at all times
- •Position work lights at low angles to reveal imperfections
First Pass with 120-Grit
Start with the coarser grit to remove high spots and ridges:
- •Attach 120-grit paper to your pole sander
- •Use light to medium pressure - let the paper do the work
- •Work in circular or figure-8 motions to avoid grooves
- •For angled ceilings, adjust your pole sander head to match the slope
- •Use a hand sanding block in tight corners and knee wall junctions
Warning: Never sand through to the brown paper face of the drywall. If you see brown, stop and apply more compound to that area.
Inspect with Raking Light
Thorough inspection reveals problems before painting:
- •Hold a bright work light at a low angle to the wall surface
- •Move the light slowly to cast shadows on any imperfections
- •Mark problem areas with a pencil for additional sanding
- •Run your hand over surfaces to feel bumps or ridges
- •Large divots may need another coat of compound before final sanding
Second Pass with 150-Grit
The finer grit creates the smooth finish you need:
- •Switch to 150-grit sandpaper on your pole sander
- •Use lighter pressure than the first pass
- •Focus on feathering edges where compound meets bare drywall
- •Blend all transitions until you cannot feel the edge
- •Continue until surface feels glass-smooth to your hand
Clean and Final Inspection
Thorough cleanup prepares walls for priming:
- •Vacuum all wall and ceiling surfaces with brush attachment
- •Wipe surfaces with a slightly damp microfiber cloth
- •Allow walls to dry completely before priming
- •Do final raking light inspection from multiple angles
- •Clean or replace HVAC filters after dust settles
Pro Tips
- ✓Use a vacuum sander attachment to capture dust at the source - essential in enclosed attic spaces
- ✓Sand in the morning and inspect in afternoon light from the windows - changing light reveals different flaws
- ✓Replace sandpaper frequently - dull paper creates more dust and requires more effort
- ✓For tight knee wall corners, wrap sandpaper around a sanding sponge for better control
Frequently Asked Questions
What grit sandpaper is best for drywall?▼
Start with 120-grit sandpaper to remove high spots and ridges, then switch to 150-grit for final smoothing. Never use anything coarser than 100-grit as it can damage the drywall paper face. For touch-ups after priming, 220-grit works well.
How do I sand attic drywall on angled ceilings?▼
Use a pole sander with a swivel head that adjusts to different angles. Work in sections, following the slope of the ceiling. For knee walls and tight areas where the ceiling meets the wall, switch to a hand sanding block or sponge for better control.
How can I control drywall dust in an attic?▼
Seal the attic access opening with plastic sheeting, close HVAC vents, use a vacuum sander attachment, wear an N95 respirator, and run a box fan with a furnace filter attached pointing out a window. Clean up frequently as dust accumulates quickly in enclosed attic spaces.
Should I wet sand drywall in an attic?▼
Wet sanding with a damp sponge is excellent for final passes as it creates virtually no dust. However, it takes longer and requires more skill to avoid over-wetting the compound. Use wet sanding for touch-ups and hard-to-reach areas, and dry sanding with a vacuum attachment for large surfaces.