How do you know whether the finish you’re thinking of re-coating is adequately adhered to the wood? If it isn’t, you won’t get by with just a screening and a recoat. The floor needs to be sanded to the wood first. What if you’ve just finished a floor, but for some reason have a nagging doubt about whether the finish is going to stay put? Perhaps you’re using a new combination of stain and finish. There’s a simple way to test finish adhesion. Find an inconspicuous spot and try to pull up the finish deliberately.
Select an area free of blemishes and use a razor knife to crosshatch a pattern spaced %4 in. apart down to bare wood.
The test area should be approximately 3/4 in. by 3/4 in. Gently brush off the test area. Place packing tape over the test area and rub it down with finger pressure. Pull off the tape at approximately a 180° angle. If small flakes of finish detach on no more than 20% of the test area, the adhesion is good. If flakes detach over 25 to 35% of the area, the adhesion is fair. More than that indicates a floor that should be sanded to bare wood before refinishing.