How to Fix Tiny Gaps in Wood Floors

Vacuum the wood floor thoroughly, removing dust and any other form of debris from the surface.

Select a color of wood filler that matches the wood perfectly. If you have a variety of wood that changes color as it gets older, like cherry, select a wood filler shade that matches how the wood will age.

Scoop out a wad of filler with your putty knife and push it into the cracks. Use a trowel to force the filler deep down into the cracks, to the tongue level. Wipe up the excess filler with a damp cloth. Allow the filler to dry for 2 hours or so.

Dip your putty knife back into your container of wood filler, scooping out another amount. Wipe the knife against the gaps and push it downwards with your trowel. Wipe away the excess filler with your damp cloth. Allow the filler 2 to 3 hours to dry.

Dip your 1-inch brush in clear polyurethane and go over all the cracks with polyurethane finish. Allow it to dry overnight and then apply a second coat, letting that coat dry for 24 hours before you walk over these areas.