What goes wrong with hardwood other than noise
Apart from squeaks, hardwood fails in three ways: it cups or crowns from moisture, it gaps from drying, and it gets damaged. Cupping, where the edges of a board sit higher than its centre, happens when the underside of the flooring holds more moisture than the top, usually from a damp basement, a slab without a proper vapour barrier, or a spill that reached the subfloor. Gapping is the opposite: boards shrink away from each other as indoor air dries out over a long heating season, opening lines you can see. The National Wood Flooring Association treats gaps that open and close with the seasons as normal, and advises keeping a home between 30 and 50 per cent relative humidity year-round. Crowning, where the centre sits proud, often follows a cupped floor that was sanded flat before it had dried. Then there is plain damage: a board split by a dropped weight, a section worn through its finish in a doorway, or staining after a leak. All of these are board-level problems, which means they can be board-level repairs, without touching the rest of the floor.