Hardwood Floor Sandpaper: Grits, Abrasive Types, and Why They Matter

Not all sandpaper is created equal. And when it comes to sanding hardwood floors, using the finest sandpaper available doesn't necessarily produce the best results.

Two abrasives labeled 60-grit can behave differently, depending on the minerals used, their cutting characteristics, and how they're manufactured.

For homeowners, that might seem like a minor detail. For flooring professionals, it can mean the difference between a properly prepared surface and one that reveals sanding scratches after the finish is applied.

Understanding Sandpaper Grits

Sandpaper grit describes the size of the abrasive particles. Lower numbers indicate larger particles that remove wood and existing coatings more aggressively. Higher numbers produce progressively finer scratches.

In hardwood floor sanding, coarse grits such as 24, 36, and 40 are commonly used for removing old finishes or flattening uneven boards. Medium grits, including 50 and 60, refine the surface, while 80, 100, and sometimes 120 prepare the wood for finishing.

Finer abrasives, including 150, 180, and beyond, have specialized applications, including certain final sanding procedures and between-coat abrasion.

But there's no universal sequence for every hardwood floor.

The National Wood Flooring Association (NWFA) recommends starting with the finest abrasive capable of removing the existing coating or correcting surface irregularities.

Why? Because every sanding pass leaves scratches that must be addressed by subsequent passes.

Jump directly from 40 to 100 grit, for example, and the deeper scratches may remain. Apply stain afterward, and those imperfections can become painfully obvious.

The Abrasive Material Matters Just as Much

Here's where sandpaper gets interesting.

Aluminum oxide remains a popular abrasive because of its versatility and consistent performance. Silicon carbide, known for its sharp cutting edges, is commonly used in fine sanding and between-coat abrasion.

Zirconia alumina is tougher and designed to maintain its cutting ability under demanding conditions. As the abrasive wears, portions of its grains fracture, exposing new cutting edges.

Ceramic abrasives take the technology further. Their engineered grain structures can provide aggressive cutting performance and extended abrasive life, particularly when removing tough factory-applied coatings.

But a ceramic abrasive isn't automatically superior to aluminum oxide for every stage of sanding.

A mineral designed to remove coatings aggressively may leave a different scratch pattern or affect wood fibers differently from an abrasive intended for final preparation.

The backing material, grain distribution, bonding system, and resistance to clogging also influence performance.

In other words, buying sandpaper based exclusively on the grit number ignores much of what determines how it actually works.

What's New in Hardwood Floor Abrasives?

Abrasive manufacturers continue developing products specifically for the challenges of professional floor sanding.

Modern ceramic abrasives, including Norton's Blaze products and Bona's ceramic systems, are engineered to remove difficult coatings efficiently while maintaining useful cutting performance.

Other developments include anti-clogging coatings, improved grain distribution, anti-static materials, and mesh-backed abrasives that improve dust extraction when used with compatible equipment.

Diamond abrasive systems are also available for removing particularly resistant factory-applied coatings.

These technologies can improve productivity, but there's a distinction worth making.

An abrasive that removes material faster doesn't necessarily leave a better surface for finishing.

The most aggressive product isn't always the appropriate one, particularly when preparing wood for stain or a penetrating finish.

Can Hardwood Floors Be Sanded Too Fine?

Yes.

Excessively fine sanding can affect how certain wood species absorb stains and penetrating finishes. A surface polished beyond what the finishing system requires may produce uneven or lighter coloration.

The objective isn't to achieve the highest possible grit number. It's to create a consistent surface appropriate for the wood and the finish being applied.

At Brazilian Floors, we follow NWFA sanding principles and select abrasive materials and grit sequences according to the conditions of each project.

Different wood species, existing coatings, equipment, and finishing systems can require different approaches.

Understanding how abrasive materials behave is part of that decision.

So, if someone tells you that using 120-grit sandpaper is automatically better than stopping at 100, or that all 60-grit paper performs alike, there's a reasonable question to ask:

Better for what?