It is really an unpleasant experience when you beautiful floor boards get cupping or crowning. Cupping is a specific type of warping when a panel becomes “U” shaped across the face, which is mostly caused by a moisture variance or imbalance through the thickness of the board. “It is an obvious sign of a moisture problem in either the substrate ie the concrete slab to which the floor is fixed, or a damp sub-floor area. It can also occur where the floor has been flooded with water and the top surface of the board dries out or absorbs less water than the lower portion of the board. … Another common scenario is where boards are heavily exposed to sunlight (eg a sun room) compounded with restricted airflow to the bottom surface.” Repairs should not be made before identifying the source of moisture, which might be
- Leaks: building, plumbing, overflows, dishwasher or refrigeration…
- Rain through an open window or spillage
- No curtain or blinds protect board from too much sunlight
- Poor drainage
- Wet or damp basements
- Sub floors with excessive moisture
- Bad ventilation
Sanding and polish should be taken after the source of moisture is resolved and the floor stabilized. For floating floor boards, they usually can be replaced easily by new boards if you have spares available.