What Is Sandpaper Grit for Floor Refinishing?

Sandpaper grit is the size grade of the abrasive particles, not a rating of how hard or durable your floor is. For many solid wood floors, a sanding sequence starts at 36 or 40 grit, then moves through 50 or 60 and 80, often ending at 100. The right sequence depends on the floor, its condition, and the finish system.

A low grit number sounds like a small detail, but it can decide whether sanding removes old finish cleanly or leaves scratches that show through the new coat. Go too coarse and you may remove more wood than needed. Jump too far ahead and the next pass may not erase deep scratches.

The aim is not to use the most grits. It is to remove the old finish and even out the wood with the least material removal that gets the job done.

What floor-sanding grit means

Grit is a grade for the size of abrasive particles on sandpaper or a sanding screen. Lower numbers are coarser and cut more aggressively; higher numbers are finer and leave smaller scratches. Grit does not tell you how durable a floor is, and labels may vary between abrasive standards.

Abrasives may follow ANSI/CAMI or FEPA grading systems. FEPA grades often carry a “P” before the number, such as P80. Do not assume that a number from one system matches the same number in another exactly. Check the abrasive label and follow your sander, flooring, and finish instructions.

For floor sanding, the grit number is only part of the decision. The wood species, type and thickness of the flooring, existing finish, sanding machine, and final coating all affect which grit will work. A wood-floor sanding sequence is not for concrete. Concrete needs purpose-made diamond tooling.

Key point: Treat grit as a guide to cutting action, not a promise of a particular result.

Inspect the wood floor, moisture, and subfloor before sanding

Before choosing sandpaper, check whether the floor is sound enough to sand. Sanding can remove finish and smooth wood, but it cannot fix loose boards, unstable parquet, a weak overlay, or joist movement. Inspect the floor, find out what it is made of, and look for hazards before disturbing old materials.

Start by identifying solid wood, engineered wood, or another surface. On engineered flooring, the visible wood layer may be too thin for a drum or belt sander. Earlier sanding may also have reduced the wear layer on solid wood. If you cannot confirm that enough wood remains, ask a qualified flooring professional before using coarse abrasives.

Then check for loose boards, protruding fasteners, damaged areas, and signs of moisture. Secure loose boards and remove or set protruding fasteners before sanding. Moisture limits are not one-size-fits-all. They depend on factors such as species, board width, site conditions, and the flooring or finish system. For refinishing, investigate unusual or changing moisture rather than treating an installation guideline as a pass-or-fail rule.

If wood flooring is being installed or repaired, confirm that the framing and subfloor meet the flooring manufacturer’s requirements. A commonly cited minimum joist deflection guideline for wood flooring is L/360, but the product and floor assembly may require more. Test a suspect slab using the method and limits specified by the flooring or adhesive manufacturer.

Do not sand unknown old coatings until you have assessed the hazards. Old paint may contain lead, and some resilient flooring or adhesives may contain asbestos. Have suspect materials assessed before disturbing them.

Key point: If the floor is unstable, too thin to sand, or unsafe to disturb, change the plan before selecting grit.

Choose the grit sequence and sand with controlled, progressive passes

A sanding sequence is a planned move from coarse to finer abrasive. Each pass should remove the scratches from the previous pass while taking off only the wood needed to reach a smooth, even surface. For many solid wood floors, a typical sequence is 36 or 40, then 50 or 60, then 80, and often 100 grit.

The table is a starting guide, not a fixed recipe. Choose the coarsest grit that can remove the finish without unnecessary wood loss. A very fine starting grit may polish the surface while leaving old finish behind; a very coarse grit can cut deep scratches or expose the floor’s limits.

Do not skip more than one step in the sequence you choose. For example, if your selected progression uses 40, 60, 80, and 100 grit, do not jump from 40 to 80. The 80 may fail to remove the deeper scratches left by 40. Change direction or overlap passes as appropriate for the machine and board layout, and inspect the floor before moving on.

Change abrasives when they become loaded with finish or dull. Keep the machine moving, especially at starts, stops, and board ends. Dwelling in one place can create a low spot that later passes may not remove evenly.

After the final wood-sanding pass, inspect the surface under raking light, meaning light shining across the floor at a low angle. It helps reveal scratches, chatter, and uneven areas that ordinary overhead light may hide. Correct defects before staining or coating; finish does not reliably hide sanding marks.

Key point: Move through a sequence that removes the prior scratches, and verify the result before applying finish.

Manage edges, dust, and floor-system stability

The edge of a floor usually needs a separate sander, so its sanding marks must blend with the marks left by the main machine. Dust control, safe handling, and a stable floor matter at every step. A neat-looking field can still show a visible edge band if the two areas were sanded differently.

A typical edge-sanding sequence follows the field sequence: 36 or 40, then 60, then 80 grit. Match the final edge grit to the final field grit. Use care near walls and corners. Aggressive edging can create a shallow dip called a dish-out, or a visible band around the room known as picture framing.

Vacuum dust thoroughly and follow the coating maker’s cleaning instructions before applying stain or finish. Use the dust collection and protective equipment required for your tools and materials. Do not disable dust collection or ignore the risk of airborne dust and ignition. For old coatings or flooring, assess lead and asbestos hazards before sanding or otherwise disturbing them.

Key point: Match edge work to the field, and plan dust control and hazard checks before sanding begins.

Apply finish, screen between coats, and protect the floor

The final wood-sanding grit should suit the stain or finish system, not simply be as fine as possible. Some finishes call for a particular surface preparation, and very fine sanding can burnish some woods. A burnished surface may take stain or finish unevenly, so follow the product instructions rather than automatically sanding to 120 grit.

After the final wood-sanding pass, vacuum and inspect the floor. Apply stain or finish within the product’s stated temperature, humidity, and recoat limits. Once a coat has cured enough for abrasion, the finish maker may call for a light pass with a screen or pad, commonly around 150–220 grit, to remove small raised bits or improve bonding for the next coat.

This between-coat step is not another wood-sanding pass. It abrades the coating, not the floor. Remove the resulting dust as directed before recoating, and wait for the finish to cure before putting rugs or furniture back or cleaning with water.

Key point: Use the abrasive and timing specified for the coating; do not substitute a wood-sanding grit schedule for between-coat instructions.

Real-world sanding examples

These examples are illustrative, not universal prescriptions. They show how floor condition changes the grit choice. A test area and the flooring and finish instructions help confirm the approach before sanding the full room.

A solid floor with a worn finish: If the wood is sound and has enough thickness, but the finish needs substantial removal, a 36- or 40-grit start may be appropriate. The next passes must remove its scratches, such as moving through 50 or 60, then 80, and often 100 grit. Inspect under raking light before coating.

A floor with only a light sanding need: Starting at 36 grit may remove more wood than necessary. If a less coarse abrasive removes the existing finish and leaves the surface even, it may be a better starting point. Continue with a progression that removes the scratches from each pass.

A thin engineered floor: A coarse abrasive may cut through the wear layer before the floor is ready for refinishing. Confirm the remaining wood thickness and the flooring maker’s guidance first. If you cannot verify that the floor can be sanded, do not test it with a drum or belt sander.

Key point: Let the floor’s condition and remaining wood set the plan, not a schedule copied from another room.

Frequently asked questions about floor-sanding grit

These answers cover common grit choices, but the flooring and finish maker’s instructions take priority when they differ. Start by confirming the floor type and condition, then choose abrasives that can do the required work without excessive wood removal.

What grit should I start with when refinishing hardwood floors?
For substantial finish removal or leveling on a sound solid wood floor, 36 or 40 grit is a common starting point. Use a less coarse grit if it can remove the finish without unnecessary wood loss.

What is a typical grit sequence for sanding a wood floor?
A common sequence is 36 or 40, then 50 or 60, then 80, and often 100 grit. The right progression depends on the floor and finish system.

Can I skip from 40 grit straight to 80 grit?
It is better not to skip more than one step in your chosen sequence. The finer abrasive may not remove the scratches left by a much coarser one.

Should I sand a wood floor to 120 grit?
Not automatically. Use 120 only when the wood and finish maker call for it; very fine sanding can burnish some woods and affect stain or finish absorption.

What grit should I use on the edges?
Follow the field sequence, commonly 36 or 40, then 60, then 80. Match the final edge grit to the final field grit, and avoid pressing or dwelling in one spot.

What grit should I use between finish coats?
Follow the finish maker’s instructions. A 150–220 grit screen or pad is common for light coating abrasion after the previous coat has cured enough, but this is not wood sanding.

Can I use wood-floor sandpaper on concrete?
No. Concrete grinding requires purpose-made diamond tooling. Wood-floor grit sequences are not a concrete-grinding guide.

Can I sand engineered wood flooring?
Sometimes, but the visible wood layer may be too thin for sanding. Confirm the remaining wear-layer thickness and product instructions before using a drum or belt sander.

Does a higher grit number mean a more durable floor?
No. Grit describes abrasive particle size. It does not rate floor hardness, finish strength, or service life.

Conclusion: choose grit by the floor, not by habit

The right floor-sanding grit is the one that removes the existing finish and prepares sound wood while taking away no more material than needed. Inspect the floor first, use a gradual sequence, coordinate edge sanding, and check for scratches before coating. If the floor may be thin or unsafe to disturb, get it assessed before sanding.

(This article was written by one of our staff writers, Marcus Vance. Visit our Meet the Team page.)