Abstract: A hardwood flooring system formed over a base combines novel milling techniques and an elastomeric filler and sealer material to provide improved resistance to moisture intrusion and resultant damage. Flooring slats are milled so that when assembled in abutting relationship in at least one orientation, a longitudinal gap is thereby defined between adjacent members. This gap may then be filled with a suitable filler/sealer material to provide increased resistance to moisture intrusion. Novel, improved milling geometries for the slats are also disclosed.