Yes. Wood naturally takes in moisture from the air and gives it back, so when indoor air stays dry for long stretches, hardwood boards shrink. That’s why many homeowners notice small gaps between boards in winter. Some of that movement is completely normal. But when the air stays very dry for a long time, or swings between very dry and very humid, it can lead to changes you can see and hear.

Here’s why wood reacts to dry air, what usually causes it, the signs to watch for, and how to keep your floors steady all year.

Key Takeaways

  • Wood moves with the air around it. Hardwood swells in humid air and shrinks in dry air.

  • The heating season is a common cause of dry floors. Cold winter air holds little moisture, and heating your home dries indoor air even more.

  • Gaps between boards are the most common sign. Gaps that open in winter and close in summer are normal. Gaps that stay open year-round can have several causes and are worth having checked.

  • Long dry spells can bring out small cracks. Keeping humidity steady helps.

  • Raised edges or centers need a closer look. Cupping and crowning are usually linked to too much moisture, though very dry air can cause some floors to cup.

  • A humidifier helps in dry months. In humid months, a dehumidifier or air conditioning helps keep things balanced.

  • A hygrometer tells you when to act. It shows whether your home is staying within your floor manufacturer’s recommended range.

How Hardwood Reacts to Indoor Humidity

Why Wood Expands and Shrinks

Wood is a natural material, and it never stops trading moisture with the air. In humid conditions, boards absorb moisture and swell. In dry conditions, they release it and shrink. This movement is normal. Problems start when conditions swing too far in one direction or stay there too long.

What Balanced Indoor Air Looks Like

Hardwood does best when temperature and humidity stay within the range the flooring manufacturer recommends, all year long. Check the care guide or warranty information for your specific floor. Keeping conditions steady matters as much as hitting a target.

3 Common Causes of Overly Dry Hardwood

The Heating Season

Heating dries indoor air, and cold winter air holds very little moisture to begin with. Here in Northwest Vermont, the heating season is long, and wood and pellet stoves are common, which can dry the air even more. Floors can lose moisture steadily from late fall into spring.

Heat Aimed at the Floor

Heat that hits the floor directly can dry boards faster than the rest of the room. Common sources include heat registers, radiant floor heating, a nearby stove, and strong sun through uncovered windows. Where you can, redirect heat away from the floor and use window coverings during the sunniest hours.

Not Adding Moisture Back

Skipping humidification during dry months is one of the main reasons floors dry out. Without it, the air keeps drawing moisture from the wood.

Warning Signs Your Hardwood Is Too Dry

Spaces Opening Between Boards

As boards shrink, the seams between them widen. Gaps that open in winter and close again as the air gets more humid are considered normal. Wider boards naturally show wider seasonal gaps.

Gaps that stay open all year aren’t always caused by dryness. They can also come from how the floor was installed, the subfloor underneath, or past moisture exposure. If your gaps don’t close in summer, have a professional take a look.

Boards That Rise at the Edges or Center

Cupping is when a board’s edges sit higher than its center. Crowning is the reverse, with the center higher than the edges. Both come from a moisture imbalance between the top and bottom of the boards, and they are most often linked to excess moisture, such as a leak, a damp basement or crawl space, or too much water during cleaning.

Dry air can cause cupping too, especially in engineered hardwood. Solid boards that cup from dryness usually show gaps as well. Because the cause could point in either direction, have the floor checked before you change your humidity.

Small Cracks in the Wood

Fine cracks along the grain, called checks, can appear or become more noticeable when humidity stays below the manufacturer’s recommended range for a long time, or when a floor cycles between very dry and very humid conditions. Raising humidity can make them less visible. Depending on the floor, small repairs or board replacement are options.

More Creaks Underfoot

As boards shrink, the fit between them changes, which can cause new squeaks, pops, or creaks. An occasional squeak is normal in any wood floor. New or widespread noise is worth a closer look.

Keeping Hardwood From Drying Out

Steady indoor humidity is the best protection. Here are the most practical ways to do that.

Adding Moisture to the Air

A humidifier helps protect hardwood through dry months.

  • Whole-home systems work with your home’s heating system to add moisture throughout the house, so you don’t have to manage it room by room.

  • Portable units can balance humidity in rooms with hardwood. They’re a practical option in homes heated mainly by a wood or pellet stove.

Balance goes both ways. During humid summer months, a dehumidifier or air conditioner helps keep your floors from absorbing too much moisture.

Tracking Humidity With a Hygrometer

A hygrometer is a simple gauge that reads indoor humidity. Place one in the areas with hardwood and check it regularly, especially during the heating season. Compare the reading to your floor manufacturer’s recommended range and adjust your humidifier as needed.

Managing Airflow

Ventilation keeps your home healthy, but in winter it can also carry moisture outside. If your home stays dry even with a humidifier running, ask your HVAC contractor whether your ventilation setup suits a cold climate. On the coldest days, keep windows closed during the heating season and save fresh air for milder weather.

Cleaning the Right Way

Check your floor’s warranty or manufacturer’s guidelines first. In general, use a pH-neutral cleaner made for hardwood and a damp (not wet) microfiber mop. Avoid vinegar, ammonia, oil soaps, and steam mops, which can dull or damage the finish or add excess moisture.

How Our Shelburne Team Can Help

Gaps, cracks, and raised edges can look similar, but they don’t always share the same cause. Some are normal seasonal movement. Others point to a humidity issue or a hidden moisture source. Getting the cause right keeps you from treating the wrong problem.

During a Free In-Home Consultation, the local team can look at what’s happening with your hardwood and talk through your options. If you’re choosing new flooring, your Design Associate can help you find a floor suited to Vermont’s long heating season and humid summers. Engineered hardwood, for example, uses cross-layered construction that keeps it especially stable as humidity changes.

Our Mobile Flooring Showroom® brings thousands of options right to your door, so you can compare materials in your own light and space. Contact us to schedule your Free In-Home Consultation. We serve Shelburne, Burlington, South Burlington, Williston, Essex, Colchester, Charlotte, and surrounding Northwest Vermont communities.