Reading the signs
- Cupping: board edges higher than the centers. Usually means moisture is coming from below (wet subfloor or crawl space).
- Crowning: centers higher than edges. Often happens when a cupped floor is sanded before it has dried.
- Buckling: boards lifting off the subfloor. A sign of heavy saturation; these sections usually need replacing.
- Dark or black stains: water reacting with the wood or finish, or mold. Deep stains rarely sand out.
Can the floor be saved?
Often, if the water is stopped quickly and the floor and subfloor are dried thoroughly. Wagner Meters notes that most floors cupped by leaks or water damage flatten again once the source is fixed and the floor dries out, and that fans and a dehumidifier can speed this up (Wagner Meters: Can wood floor cupping be fixed?). The key mistake is sanding or refinishing too early: wait until moisture readings in the wood and subfloor are back to normal.
How pros dry wood floors
- Stop the leak and remove standing water and wet rugs.
- Measure moisture in the boards and subfloor to map the wet area.
- Dry with dehumidifiers, air movers and, where needed, specialist floor-drying mats that pull moisture out of the boards.
- Re-measure daily. Only once readings are normal decide what to sand, refinish or replace.
Hardwood floor repair after water damage: repair or replace?
Lightly cupped boards that flatten after drying can often be sanded and refinished. Buckled, split, deeply stained or moldy boards are usually replaced, ideally with matching boards woven in. Engineered wood and laminate generally can't be sanded the same way and are more often replaced.
Insurance
If the water came from a sudden event like a burst supply line, a standard homeowners policy often covers it; a slow leak over time often isn't covered (Insurance Information Institute: Am I covered?).