Stair Tread Resurfacing: Protect Nosing, 100–180 Grit Steps

Stair treads take a beating—grit from shoes, pet claws, and years of traffic leave them dull, scratched, and uneven. You don’t have to rip them out to make them look new. With a nosing-safe setup, a simple sanding jig, and a tight grit ladder, you can flatten the field, keep edges crisp, and lay a durable finish that stands up to daily life.

Why Sanding Treads Matters

Finishes telegraph what’s underneath. If you sand inconsistently, you’ll see waves along the run, rounded nosing, and cross-grain scratches under the next coat. A controlled approach does three things: (1) levels wear tracks without dishing earlywood, (2) preserves geometry at the nosing and stringer edges, and (3) unifies the scratch field so stain or clear lays even and durable.

Tools & Supplies

• Random-orbital (DA) sander with dust extraction (low/medium speed) and a soft interface pad for gentle crowning.
• Firm hand block (flat face) and a thin foam hand pad for profiles.
• Wet/dry silicon carbide sandpaper sheets: 100, 150, 180 (optional 220 for between-coat de-nibbing).
• Edge & nosing protection: blue painter’s tape, cardboard shim, or a sacrificial nosing guard strip (L-shaped hardwood offcut).
• Simple stair sanding jig: a straight 18–24 in. fence that rides the riser, with a depth stop to keep the block square to the run.
• Vacuum with brush head, microfiber towels, and tack cloth.
• Raking/inspection light; pencil for cross-hatch guide marks; straightedge.
• PPE: respirator, ear/eye protection, and knee pads.

Recommended Grit Sequence

• 100 grit: Reset the surface—remove finish nibs, traffic ridges, and shallow scratches without digging.
• 150 grit: Replace 100’s tracks and refine the field; start checking sheen in raking light.
• 180 grit: Pre-finish smoothing for most hardwood treads (oak, maple, ash). Optional 220 between coats only.

Step-by-Step: Flat Runs, Crisp Nosing

1. Mask and guard the nosing. Tape both arrises (front nosing and wall-side edge). Add a sacrificial nosing guard: clamp or double-tape a thin L-shaped strip flush with the bullnose so your block/fence can ride against it without rounding the edge.
2. Map the surface. Under raking light, pencil a light cross-hatch over the tread. The marks show when each grit has finished its job and prevent over-sanding.
3. Reset at 100 grit. For predictable, controlled cut on flats, start by hand with a firm block or run a DA at low/medium speed, pad dead-flat, and feather-light pressure. Use a sharp sheet like 100 Grit (25-pack) to erase traffic lanes and finish nibs. Work in overlapping lanes along the run, then a brief pass with the grain. Stop when the pencil map just disappears.
4. Edge discipline & jig pass. Set your simple jig (straight fence riding the riser; depth stop slides along the stringer) and run the block against it to keep strokes square. Hand-sand right up to the nosing guard with the sheet wrapped on a small firm block—no fingertip pressure. Two strokes per edge is plenty.
5. Vacuum and inspect. Dust is abrasive. Vacuum in two directions, brush the sheet face, wipe with a microfiber, and check under raking light for shiny low islands or deep tracks.
6. Refine at 150 grit. Change your pass direction slightly to reveal leftover 100 lines, then finish with the grain. A mid-step like 150 Grit (50-pack) replaces coarse scratches quickly without burnishing. Keep the DA speed moderate; let sharp grit do the work.
7. Final pre-finish at 180 grit. Switch to 180 Grit (100-pack) and make two or three with-grain passes until the field reads uniformly satin. Pull the nosing guard and gently kiss the arrises by hand at 180 (two strokes) to keep them crisp.
8. Clean for coating. Vacuum carefully (including corners and stringers), tack lightly, and wipe handprints. If staining, avoid over-handling freshly sanded wood.
9. Finish smart. Apply stain (if used) evenly; wipe back with the grain. For clear coats, many pros choose waterborne polyurethane for fast recoat and abrasion resistance. Maintain a wet edge and respect dry/recoat windows.
10. Between-coat de-nib (optional). After the first coat cures to sandable, de-nib with a feather-light 220 hand pass on a soft pad. Vacuum/tack and apply the next coat. Don’t try to “re-level” between coats—you’re just knocking nibs.

Special Cases

Veneered/boxed treads: Veneer can be <0.6 mm; avoid coarse grits and aggressive DA passes. Start at 150 by hand, then 180. If you see a light patch, stop—spot prime and plan an opaque finish.
Deep gouges & pet damage: Lift dents with a damp cloth and iron (on raw wood only), then spot 100 by hand and re-refine. For through-finish scratches, blend wider at 100 so you don’t create bowls.
Softwoods (pine/fir): Cut slower and fuzz more. Keep pressure minimal; limit the top grit to 150–180 and test your stain for blotch.
Paint removal: Heavy paint build may need chemical strip or a scraper before sanding. Don’t try to “grind” off thick coatings with 60–80 on stair treads—you’ll dish earlywood and round edges.

Pro Tips

• Block for flats; foam for crowns. Use the firm block on the run; add a thin foam interface only where the tread crowns slightly.
• Time-on-grit discipline. Don’t climb until the previous scratch pattern is 100% replaced under raking light.
• Keep strokes square. Your fence/jig keeps the block aligned so you don’t taper the run toward the stringer.
• Fresh sheets > more pressure. Dull paper polishes, then scratches. Rotate to a fresh quadrant at the first hint of drag.
• Edge safety. Leave tape on arrises for 100/150. Remove before the final 180 hand kiss, then stop.
• Mind the dust. Treads live in traffic—vacuum adjacent flooring and risers so debris doesn’t grind into fresh finish.

Aftercare

• Respect cure times before foot traffic, furniture moves, and runners (rugs). Waterbornes feel dry fast but harden over days.
• Add felt pads to stair-top décor and anti-slip pads under runners that won’t imprint young finishes.
• Clean with neutral pH products; avoid steam mops on fresh coats.
• For periodic refresh, a quick 180–220 hand de-nib and one maintenance coat keeps treads looking new.

FAQs

• Do I need to remove the treads? No—most resurfacing happens in place. Mask thoroughly and control dust.
• Is 220 too fine on raw wood? For most hardwoods, stop at 180 before finish. Use 220 only as a light between-coat de-nib.
• Can I use a belt sander? Avoid on stairs; belts remove fast and round nosing. A DA plus a firm block is safer.
• What finish is most durable? High-quality waterborne poly offers fast recoat and abrasion resistance. Oil-modified ambers more and cures slower.
• How do I keep nosing crisp? Tape early, use a guard strip, keep the pad flat, and finish edges by hand with counted strokes.

Watch & Learn

Closing: Great stair treads come from a simple, disciplined process: protect the nosing, map the surface, then work a tight ladder—100 → 150 → 180. Use a fence or jig to keep strokes square, keep pressure light, and clean meticulously between steps. Stock the exact sheets so you can stay disciplined at each stage: reset with 100 (25-pack), refine with 150 (50-pack), and finish flat with 180 (100-pack). Your stairs will look sharp, feel smooth, and hold up to daily traffic.