Refinishing hardwood floors can completely transform the look of your home by making old, worn floors look brand new again. However, it’s important to avoid some key mistakes during the refinishing process to ensure you get the best possible results. According to the National Wood Flooring Association, there are an estimated 500 million square feet of hardwood flooring refinished each year in the United States. Here are the top 10 mistakes to avoid when refinishing hardwood floors.

1. Not Testing for Lead Paint

If your home was built before 1978, the existing finish on your hardwood floors may contain lead-based paint. It’s essential to test for lead paint before sanding or removing old finish. Breathing in lead dust can be extremely hazardous to your health. The EPA estimates that 1.7 million homes still contain lead-based paint. Have a lead testing kit ($15-$40) on hand to test corners and edges of floorboards first. If lead is detected, take proper precautions for lead paint removal which can cost $8-$15 per square foot.

2. Using the Wrong Abrasives

Sanding is the most important part of refinishing hardwood floors. According to industry surveys, using the wrong sandpaper grit is one of the biggest mistakes made by DIYers doing wood floor refinishing. Always start with a coarse 36-40 grit sandpaper to remove old finish completely, then work up to 60-80 grit for smoothness. Finish sanding with 100-120 grit before staining or sealing. Never skip grits or use overly coarse papers that can scratch wood.

3. Not Vacuuming Thoroughly Between Sanding

Vacuuming between each pass with the floor sander is critically essential. According to experts, failure to clean floors thoroughly between sanding is the number one cause of a poor final result. Thoroughly vacuum edges, corners, and crevices after each sanding pass before moving onto the next finer grit sandpaper.

4. Not Sanding with the Wood Grain

Always sand with the direction of the wood grain, moving the floor sander in the same direction as the grain. Sanding against the grain can leave visible scratch marks that won’t come out. According to a survey by HomeAdvisor, going against the wood grain is the most common sanding mistake reported. Gently feather the sander over edges and end grains to blend scratches. Apply finish in the direction of the wood grain as well.

5. Not Applying Primer Before Stain

Most experts recommend applying a primer coat after sanding and before staining. Priming seals the raw wood, prevents blotching, and allows for even absorption of stain. According to Minwax, a primer can reduce the amount of stain needed by up to 50%, saving money and creating a professional finish.

6. Choosing the Wrong Stain Color

Test different stain colors on spare floorboards first. Consider lighter tones to keep the space bright and airy. Dark stains can dominate a room and show dust easily. According to one survey, 71% of homeowners say they would have chosen a lighter stain color if they could do it again. Also test gloss level—high-gloss finishes reflect light well but show imperfections, while satin/matte is more forgiving.

7. Applying Finish Too Thin or Too Thick

Applying polyurethane or other finish too thin can leave gaps or uneven coverage. On the other hand, applying too thick of a coat can lead to runs, bubbles, or puddling. Carefully follow the product label for proper application thickness and drying times between coats. Generally, 2-3 thin, even coats works best for durability and shine. Thinner coats tend to dry faster while thicker coats require significantly more drying time between applications. Find the right balance for your climate and conditions.

8. Not Sanding Between Finish Coats

Lightly sanding between each coat of polyurethane allows the next coat to bond properly. Use fine 220-320 grit sandpaper between finish coats. Clean and vacuum completely before applying the next finish coat. The finish should appear smooth as glass after final sanding. Professionals recommend tack cloths for removing dust before recoating. Always sand with the wood grain to avoid swirl marks.

9. Not Allowing Proper Dry Time

Patience is key when refinishing floors. Rushing between steps is the number one cause of finish failure down the road. Always allow at least the minimum drying time stated on the products. Cooler temperatures or high humidity can extend dry times up to 2–3 times longer. Consider using fans to improve air circulation and speed up drying times. Schedule your project when moderate temperatures and low humidity are forecasted.

10. Not Applying a Protective Final Coat

It is important to apply a protective finish coat as the last step. While wax can provide some protection, it typically takes about 30 days to fully cure and harden on the wood floor surface. This means it is softer and less protective during that first month. In contrast, polyurethane forms a much harder protective layer that will last 3–5 years under normal use. A good quality polyurethane, water-based urethane, or moisture-cured urethane as the final coat will protect your floors for years, while wax only reaches maximum hardness and protectiveness after a 30 day curing time.

Final Thoughts

Avoiding these common mistakes during hardwood floor refinishing will help ensure you achieve beautiful, long-lasting results. Test for lead paint, use the proper sanding techniques and materials, apply products per label instructions, and exercise patience for best outcomes. Your refinished hardwood floors will look amazing for decades to come by sidestepping these top 10 pitfalls during the refinishing process.