Wood flooring problems Abnormal gaps are gaps that do not go away. They are generally caused from the flooring being too wet when installed Buckling is generally caused from excessive moisture. This floor was installed too dry. May have to replaced or repaired Crowning is generally caused from sanding a floor that was still cupped. If the moisture content of the floor is ok, resanding and finish the floor Cupping is generally caused from a difference in moisture content from the top to the bottom of the boards Damaged subfloor from leaking door Debrise contamination in finish. Flooded Subfloor, poor building practice. Wood floor will cup, buckle or have gaps someday. Fracture on the edge of a prefinished floor from nailing gun during installation Fractured prefinished floor being installed too dry for the enviroment Improper board spacing, should be at six inches Improper sanding between coats of finish Nail rust spot from water flood Pet Stains Soft wood dished out. Needs to sanded with a flat plate or Tri-planetary sander Soft wood excessive wear Stain from wet cloth hamper Subfloor storage, poor building practice The polyurethane is peeling from contamination (wax, grease, oil, etc.) or not abrading between coats of finish Water and dirt stains