During the spring and summer, the air inside a house is much more humid than during the winter. The lumber used for flooring absorbs liquid in the air and enlarges.

Crowning
Crowning is the bowing of a wood floor slat where the center of the board appears to be higher than the edges. Standing water on flooring triggers the most drastic crowning. This problem can occur spontaneously in larger planks and center cuts of timber. Naturally occurring crowning is much less severe than the kind caused by human error and can only be seen upon close inspection. This kind of crowning is often the result of a humid environment, but should go away once the wood is allowed to dry out. In the meantime, floors with beveled edges will hide some of the distortion.

Cupping
Cupping is a condition in which planks begin to resemble shallow cups as the sides rise above the center on the slat. Water spills that were allowed to soak into the wood are sometimes the problem, but high humidity is often the culprit. This condition is the result of the bottom of the floor containing more moisture than the top. Leaks in the subfloor and improper drying are usually the cause of these variations in dampness.

Buckling
Buckling is a serious flooring issue in which the wood detaches from the subfloor. This problem should never be caused by normal changes in humidity. If a floor does react in this way to more moisture in the air, it was probably installed incorrectly. Buckling is seen most often in homes that have been flooded.

Controlling Moisture and Fixing Floors
Owners of wood floors should keep their home well ventilated in the summer so that moistures can flow freely out of the house. Homes in particularly balmy climates may need the help of a dehumidifier.

Never leave standing water on a floor. After a spill, sop up the liquid as quickly as possible. If necessary, use fans, such as the Oscillating Wall Fan, to thoroughly dry the wood. It is never a good idea to mop floors or clean them with water-based products, so try the Shark VX3 Cordless Sweeper to help clean the floors.

A damaged floor may need sanding, refinishing, or other repairs. Since the floor must be dried before any work can be done, try letting it air out for a while before calling a handyman. Many humidity problems are only temporary, so watch the area for a few days. If the wood does need work, make sure to allow the moisture to escape before refinishing it.