I've heard a hundred reasons why a floor has cupped. Everyone has their own theory, however, the only reason for cupping is a moisture imbalance between the top and bottom of the wood flooring material! Either the board has gained moisture from below or lost moisture from the surface. The result is an imbalance from front to back. If dried quickly, cupping will correct itself without having to remove the floor. Floors that remain cupped for a long period of time can actually take on the new shape resulting in a permanent cupping condition. Once dried, the floor can be sanded flat and refinished providing no additional damage is present. If a cupped floor is to be sanded, it is very important that the wood has stabilized. If sanded too early, when the wood finally dries, the edges will be thinner than the center resulting is a "crowned" condition.

This graphic shows in detail a cupped and crowned condition. 

Here is a situation where a bamboo floor was glued directly to an on-grade concrete slab. It appears that the surface was not completely clean of dust in addition to allowing the adhesive to "flash-off" too long. The result is a floor that has failed. Unfortunately, the entire floor will most likely have to be removed, the concrete slab shot blasted to remove any old adhesive that has bonded and new material installed. A very costly mistake!

Who said I wasn't handy with a saw? This ragged cut could be found by nearly every vent opening in the home. A little care would have prevented this condition. As usual, this was not the only problem with the floor. The costly repairs are the responsibility of the installer. Perhaps next time he will use a little more care.

The homeowner called for an inspection because of splinters in the surface of her new hardwood floor. You can actually see some of the fibers from being snagged on her stockings when walking across the floor. According to the installer, it met the "5-second rule". In other words, if you can't see the splinter, split board or other problems with the floor within 5-seconds of entering the room, the floor meets industry standards...HUH?

Failure to leave adequate expansion space wherever a floor meets a vertical obstruction can play havoc with a solid wood floor. General industry guidelines call for a 3/4-inch expansion gap at any point where the floor may come in contact with something that will block expansion. In this particular case, the meager expansion space that was allowed was used up and the floor started to buckle. "lower the humidity" was the suggestion offered. I guess that would be cheaper than correcting the problem by removing the quarter round and cutting the floor back to allow expansion. Another alternative would be to under cut the drywall where the wood meets the wall. This would permit an additional 1/2-inch or more without cutting the floor.

Wood floors are beautiful! Fortunately most of the installers are true professionals who produce floors they can be proud of. Although I never personally recommend an individual or company (for ethical reasons) I suggest that a visit to the National Wood Flooring Association's web site will supply a list of qualified installers and finishers who would be willing to provide references.