Answer
For fiber cement siding, clean first and use 220 or 320 lightly only on rough edges or glossy spots.
Why it happens
Fiber cement needs cleaning and light scuffing only where needed before coating.
Recommended grit
Use 220 or 320 lightly on rough paint edges or glossy patches.
Wet or dry
Dry with dust control.
Success check
The siding is clean, stable, and ready for paint.
What to do
- Clean the siding first.
- Remove loose paint or chalky residue.
- Sand rough paint edges with 220.
- Use 320 for smoother visible prep.
Avoid: Do not aggressively sand fiber cement dust without proper protection.