Fixing Dark Areas Of Polyurethane With An Orbital Floor Sander


We have an old wood floor with what we think is a “pickled” looking polyurethane finish that seems to have been laid on an older, darker finish. The older finish is now exposed in high-wear areas, so the floor looks unsightly. We have been told that the floor cannot take another sanding, so we are looking for options to fix the existing finish. A paste wax was applied to the floor within the past two year or two.

Can we lightly hand-sand the worn areas and apply a new coat of polyurethane? Do we need to strip the wax after this much time? If yes, then how? Does the pickled color of the finish come from a tint in the polyurethane, or was another treatment used? We would prefer a more golden color, is there any way to achieve it without sanding off the old finish?



Dear John

I’m afraid your old floor finish is beyond salvaging, mainly because you have waxed the floor. It is difficult to remove all the wax from the wood, and then expect the poly to stick to the wood. In fact in most cases with waxed floors, they need to be completely sanded to the bare wood and refinished. But it you are sure that the floor cannot be resanded, don’t worry, because the floor can be chemically stripped instead. And here is the text version of my stripping article.

Oh, and if there is large grey areas left after the chemical stripping, use a Orbital Floor Sander (free article on this tool in the web site) to gently remove these after the floor has dried for a couple of days after the stripper. In your case a light colored wood stain would be good to apply to the whole floor to even out the color. But like the article suggests do a small sample of the whole process to see just what works best.

I don’t know if the pickling effect (possibly a decorative grain filler) will come off with the stripper, only doing the sample will tell. But if it doesn’t the Orbital Floor Sander with 80 grit paper will remove the last of it, and a medium colored wood stain will help blend it in.

As always your Most humble servant, Joseph, the Wood Floor Doctor.