Hardwoods & moisture

Q: The old hardwood floors in my parents’ house are a mess. I want to repair them and use as much of the original wood as possible. Any advice? — Nichole S.

A: Just because hardwood flooring is old does not means it should be badly deteriorated. Hardwood flooring can last for centuries. There probably are some underlying problems that are causing the deterioration. Before you start your project, search for new hardwood that matches the existing floor. This way, you will be able to reuse some of the old floor.

Buckling and cupping are usually related to moisture issues — either too much or too little. The humidity level in homes can vary significantly from January to June. Even though the hardwood seems to be sealed with a durable urethane coating, moisture will get into the wood.

As the moisture content of any wood increases, it expands. When it dries, it contracts. This is the cause of cupping.

Find the source of the moisture under the hardwood and block it as much as possible. Don’t just take a sander to the installed cupped hardwood and sand it flat. It may look good for a month or two, but when the moisture level changes, it may end up being crowned instead of cupped.

Buckling of a hardwood floor is also related to moisture issues. Usually, the hardwood flooring was installed when it was too dry and in its contracted size. When it adjusted to its normal moisture level, it expanded.

As it expands, the gap between pieces shrinks until it is gone. At this point the hardwood has no place to go other than buckling up.