Wood can expand in the winter and contract under dry conditions
Wood floors are a staple in many homes, but knowing how to maintain hardwood is important for ensuring the flooring lasts for decades. One crucial component is understanding how wood floors change from season to season. Does wood expand in cold weather, or will it contract? Find out what to expect and how to prevent damage during extreme temperatures.
Temperatures can impact wood, but this flooring material is more impacted by changes in humidity. This all comes down to the cells that form structures for sap to travel through. Once chopped for lumber, the sap dries up, leaving tubular structures that shrink or expand based on the presence of moisture.
Once the sap dries up, the tubular structures of the wood will shrink if the air is dry. But if there’s rain, snow, or humidity, those structures will absorb the moisture, swell, and expand the wood.
Wood might experience some thermal expansion as temperatures rise above an ideal 75°F, but the impact is minimal in comparison to how wood changes based on moisture content.
Humidity is the main factor that changes how floors expand or shrink. The ideal humidity level for wood is 35% to 55%. If the temperature is high, which might typically cause a little bit of expansion, but the moisture content is low, which causes shrinkage, the net result is shrinkage rather than expansion.
It’s common to think that cold weather leads materials to shrink. But that’s not always the case. If you live somewhere that gets cold and dry in the winter, then you can expect the floors to shrink.
But let’s say you kick off your snowy boots by the front door, letting them land on the wood floors. As the snow melts into the wood floors, the moisture content increases and causes the wood to expand. This is one common problem for hardwood floors, as floors can warp or swell with long-term water exposure. If you have already noticed damage, hire a local floor repair contractor to assess and fix warped, swollen, or split floors.
If you live in an area with hot, dry summers, like the deserts in the southwestern U.S., you can expect wood floors to shrink due to a lack of moisture content in the air. But in many places, summers can mean hot and humid air. While you’re sweating as you clean the house, the wood floors are absorbing the moisture from the humid air and expanding.
So what does it look like for wood to expand or shrink? Wood actually only changes perpendicular to the grain, so it will not shift parallel to the direction that the grain runs. This can be important to note when choosing wood floor planks and installing wood flooring, so you can plan for which way the floors may shrink or expand. Floors can shift up to 1/4 inch due to expansion or shrinkage.
Shrinking, swelling, and even some splitting is normal for wood over its lifetime. But especially if you live in a climate with extreme temperature changes, it’s best to be proactive to keep the wood from changing too much. Here’s how to care for wood floors in every season.
Spring temperatures are typically mild, but watch out for excessive April showers. Add a boot tray by all entry points to store wet shoes off the floor, and keep a mop handy to absorb any water that might be tracked in. Be sure to wipe muddy paws, too.
When it’s time for spring cleaning, consider cleaning finished wood floors with a solution of ½ to 1 cup of white vinegar in one gallon of warm water rather than relying on harsh cleaners.
If summer is hot and dry, measure indoor humidity levels with a hygrometer, which is an inexpensive tool you can find at most hardware stores or major retailers. Turn on humidifiers as needed. If summer is humid for you, again, make sure you measure the air humidity level, then turn on a dehumidifier or even an air conditioner to help keep indoor humidity levels low.
Similar to spring, keep a boot tray by the front and back doors to hold boots that might be muddy or wet. Use a gentle cleaner when damp mopping, and regularly sweep or vacuum to clean up dirt and dust. Toward the end of fall, keep an eye on humidity levels. If the air is drying out, consider adding humidifiers to rooms with wood floors.
Keep snowy shoes off of the floors, and be sure to sweep and mop up any sidewalk salt that might make its way into your foyer. Keep humidifiers in rooms with wood floors if the air is dry. Use a hygrometer to measure air humidity, with the ideal level at around 35% to 55%. Be sure to look out for any scratches on your wooden floors, as these can crop up no matter the season.
