Owners of wood floors are often surprised to find cracks and bows in their pristine flooring throughout the year. These small cosmetic concerns are common to all types of commercial flooring and are no reason to panic. 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.

All wood floor systems are designed to withstand a certain amount of moisture. In most cases, plenty of space is left during installation between planks in order to allow the material to expand. Even engineered and composite wood floors go through the same changes as solid wood, but often include special channels that allow the material to grow. These measures are designed to prevent problems caused by too much moisture, but the appearance and integrity of the floor can still be affected by high humidity.

Crowning is the bowing of a wood floor slat into a convex shape. The center of the board appears to be higher than the edges and makes the floor uneven and unattractive. There are a number of causes for crowning, but it is often the result of botched attempts to fix other moisture problems. 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 is a condition in which planks become concave. The pieces of wood begin to resemble shallow cups as the sides rise above the center on the slat. There are a number of reasons severe cupping can occur in a floor, but moisture is always to blame for the change in the wood. 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.

The treated surface of the wood resists expanding, but the seams and underside of the planks swell. As each piece grows, the planks can begin to push against one another. This pressure can exacerbate the cupping by forcing the edges to rise even more and cracks the wood.

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.

Most homeowners will have no problem with their floors. Most modern flooring has been treated and designed to withstand even the most drastic atmospheric changes. If these products are installed properly, the planks should have enough room to grow without any problems.

However, 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. Cracks happen most in the winter, and although they are often only temporary, it may be wise to introduce some moisture into the air inside via a humidifier. This can help the family avoid colds and soar throats, too.

Never leave standing water on a floor. After a spill, sop up the liquid as quickly as possible. If necessary, use fans to thoroughly dry the wood. Of course, it is never a good idea to mop floors or clean them with water-based products.

If a floor has been damaged, look for leaks and other more significant sources of moisture. Humidity does not often cause permanent cosmetic defects, so check for other common problems first.

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. Trapping extra water inside is likely to cause crowning.