Q imported from our old site, Face Lift Floors: I have a red oak HW floor that was installed in a new house the late summer of 2002. No gaps have developed anywhere in the entire house, save an 8ft run between two planks in the kitchen. The gap is 1/8th of an inch.
We have humidity control. How can we repair this and still have the floor look great? Can a thin piece of oak be cut, glued, stained and finished in this isolated area? At the very least is it possible to have a stained piece of oak inserted and glued into the gap/crack?
A: This sounds to me like a problem with the subfloor itself, possibly the result of some settling of the building. I think it is likely that the gap between these 2 boards falls on a plywood seam. I trust you do have plywood and not espanite.
My first effort to cosmetically fix this crack would be to use a color matched filler. Either a paste manufactured by Bruce Hardwood floors or one from Dura Seal. Just rub/push the filler into the crack and wipe the residue off the floor surface.
Adding… I would suggest you go to the nearest hardwood flooring retailer and buy a couple of jars of Dura Seal wood putty, which comes in a variety of colors. Work it into the crack with your fingers, and wipe the residue from the floor surface with a cloth dampened in mineral spirits.
Original / moved link https://faceliftfloors.com/q-and-a/crack.php