Hardwood flooring is one of the most beautiful and long-lasting flooring options you can put in your home. But because wood is a natural product, it responds to its environment in ways that sometimes surprise homeowners—especially here in the Boise and Meridian area.

If you’ve ever noticed small gaps between planks in the winter or floors that feel a little tighter in the summer, you’ve seen hardwood expansion and contraction in action. The good news? This is completely normal. Understanding why it happens—and how to manage it—will help you enjoy your floors for decades.

Every homeowner with hardwood floors will see some level of seasonal movement. Whether you have solid hardwood or engineered hardwood, all wood contains natural fibers that take in and release moisture.

Boise & Treasure Valley homes are especially affected because we have dry winters and warm summers.

Families running furnaces in the winter often notice small cracks, while summer humidity can cause wood to expand.

​Even brand-new hardwood floors from the best manufacturers will move—it’s part of the nature of wood.

Winter: The Boise climate is dry, and heating systems pull even more moisture out of the air. Expect to see more gaps and contraction.

Spring & Summer: Warm air carries more moisture, so floors swell slightly and gaps diminish.

​This cycle repeats year after year, and while it can surprise new hardwood owners, it’s completely normal.

You can’t stop wood from responding to its environment, but you can minimize extreme changes with a few smart habits:

Use a humidifier in winter to add moisture back into the air. Even simple tricks like boiling a pot of water on the stove can help.

Avoid over-humidifying in summer. Run air conditioning or a dehumidifier if indoor humidity climbs too high.

Keep temperatures consistent year-round. Sudden swings in heat and humidity make wood move more dramatically.

Plan for seasonal gaps. A small gap in winter doesn’t mean your floor is defective—it’s simply part of owning natural hardwood.

Keep indoor humidity 35–55% year-round

Run a humidifier in winter if air feels dry

Place rugs or mats in front of sunny slider doors and windows

Don’t panic at small winter gaps—they’ll likely close in summer

​Call a flooring professional if gaps are large or don’t close seasonally

1. Do engineered hardwood floors expand and contract less?
Yes. Engineered wood is designed with multiple layers, which makes it more dimensionally stable than solid hardwood. But it will still move slightly with the seasons.

2. My hardwood has gaps in winter—should I be worried?
Small seasonal gaps are completely normal. If gaps are unusually wide or remain open year-round, it may be worth an inspection.

3. What happens if my home is too dry?
Excessive dryness can cause more noticeable gaps, cracking, or even splitting. Adding humidity helps keep floors healthy.

4. What happens if my home is too humid?
Too much moisture may cause cupping (edges higher than the center) or buckling. A dehumidifier or air conditioning helps reduce excess humidity.

5. Can I prevent expansion and contraction completely?
No. All wood will naturally expand and contract. The goal is to minimize extreme changes with proper humidity control.

Hardwood expansion and contraction is a natural process, especially in climates like Boise’s. By maintaining indoor humidity between 35–55% year-round, you’ll minimize gapping in the winter and swelling in the summer—keeping your floors beautiful for decades.

At Capell Flooring & Interiors, we’ve been helping Boise and Meridian families with hardwood floors since 1974. Whether you need advice on humidity control, professional refinishing, or brand-new hardwood installation, our team is here to help.

​👉 Learn more about hardwood care or schedule a consultation today: Capell Flooring Hardwood Services