To protect a hardwood floor in Quebec, hold indoor relative humidity between 35 and 55 percent all year. Wood is a living material that swells in damp air and shrinks in dry air, and our winters routinely push heated homes below 25 percent. That dryness, not cold itself, is what gaps, cracks, and cups hardwood floors. A hygrometer and a humidifier fix it.

Why Dry Winter Air Is The Real Enemy?

Cold does not damage a hardwood floor. Dry air does. When outdoor temperatures drop and the furnace runs for months, indoor air loses its moisture, and a heated Quebec home in January often sits between 15 and 25 percent relative humidity. Desert air is drier than that, but not by much. Wood constantly trades moisture with the air around it. In that parched winter air, each board gives up moisture and shrinks across its width. Multiply a small shrinkage across dozens of boards and you get visible gaps between planks, the hairline checks people call winter cracks, and in bad cases boards that pull at their edges. Come summer, the humid air swells everything back, and the gaps close. The floor is not failing. It is doing exactly what wood does, and your job is to narrow that swing.

The Target Range And What Happens Outside It

Manufacturers and the National Wood Flooring Association build their warranties around a stable indoor climate. Below 25 percent, the floor shrinks, gaps open, and edges may check (deep winter with no humidifier). At 25 to 34 percent, you see noticeable gapping and the floor feels dry (late winter). At 35 to 55 percent, the floor is stable with minimal movement, and this is the target (well-managed year round). At 56 to 65 percent, there is slight swelling and gaps close tight (humid summer). Above 65 percent, you get cupping, swelling, and finish stress (summer with no dehumidifier or AC). Aim to live in that middle band. The exact number matters less than staying inside the range and avoiding fast swings from one extreme to the other.

The Three Tools That Hold The Range

You cannot manage what you cannot measure, so start with a reading and work from there. Three inexpensive tools do the whole job. A hygrometer is a small humidity gauge, often ten or fifteen dollars, that tells you the actual relative humidity in the room. Put one near the floor in your main living area and check it weekly through winter. A humidifier adds moisture in the dry months, either a portable unit for a room or a whole-home model plumbed into the furnace for a house-wide fix. An HRV, or heat recovery ventilator, is common in newer Quebec homes and balances fresh air with humidity control, though in deep winter you may still need to add moisture on top of it. Together they let you hold the range instead of hoping for it.

Also Read – Hardwood Flooring Maintenance Tips for Quebec Winters

A Simple Year-round Routine

Managing humidity is a rhythm, not a one-time fix. It follows the calendar. In fall, before you fire up the furnace, place or check your hygrometers and service the humidifier so it is ready. Through winter, run the humidifier and watch the gauge, topping up moisture whenever the reading dips under 35 percent. In spring, ease off as outdoor air warms and the indoor level climbs on its own. Through summer, the risk flips to too much humidity, so run air conditioning or a dehumidifier if the reading climbs past 55 to 60 percent. This loop keeps the floor inside its comfort zone in every season and prevents the hard swings that cause the worst damage.

Reading The Warning Signs Early

Your floor will tell you when the air is wrong, if you know what to look for. Thin gaps opening between boards in January mean the air is too dry, so raise the humidity. Hairline cracks in the finish or a dry, papery sound underfoot point the same way. If boards feel raised or springy at the edges in a humid August, that is cupping from too much moisture, and it is time for a dehumidifier or more air conditioning. A cluster of these signs in one area often points to a specific source, a nearby humidifier running too hard, a leaking window, or a damp spot below. Catch the pattern early and a two-dollar adjustment on the gauge prevents a floor-wide problem.

The Habit That Outlasts The Floor

“I have replaced floors that had nothing wrong with the wood or the install, they were simply starved of moisture every winter for a decade,” says Sefi Dollinger, Owner of Planchers Bellefeuille. “A fifteen-dollar hygrometer and a humidifier would have saved the whole floor. I tell every customer the same thing before they leave the showroom: buy the gauge the same day you buy the floor. Keep the house between 35 and 55 percent, watch it in January, and your hardwood will look as good in twenty years as the day we laid it.”

Frequently Asked Questions

1. What humidity should I keep my house at to protect hardwood floors?

Keep indoor relative humidity between 35 and 55 percent year round. That range keeps hardwood stable and minimizes the shrinking and swelling that cause gaps and cupping. In a dry Quebec winter you will need a humidifier to reach the low end, and in a humid summer, air conditioning or a dehumidifier to stay under the top.

2. Why do gaps appear in my hardwood floor in winter?

Dry winter air pulls moisture out of the wood, so each board shrinks across its width and small gaps open between planks. It is normal seasonal movement, and the gaps usually close by summer. Running a humidifier to hold 35 to 55 percent relative humidity keeps the gapping to a minimum.

3. Will a humidifier stop my floors from gapping?

Largely, yes. A humidifier that keeps indoor air at 35 percent or above through winter prevents the extreme dryness that causes visible gapping. A whole-home humidifier on the furnace works best for an entire floor, while a portable unit can protect a single room. Pair it with a hygrometer so you know you are hitting the target.

4. What happens if my house is too humid in summer?

Above roughly 60 to 65 percent relative humidity, hardwood absorbs moisture and swells, which can push boards tight, stress the finish, and cause cupping where board edges rise. Run air conditioning or a dehumidifier in humid months to hold the range. Both too dry and too damp cause problems, so the goal is the stable middle.

5. Do I need a hygrometer if I have an HRV?

Yes. An HRV helps balance humidity, but it does not guarantee your floor sits in the 35 to 55 percent range, especially in deep winter when you may still need to add moisture. A cheap hygrometer confirms the actual level near the floor so you can adjust rather than assume.

6. Does radiant heating dry out hardwood floors more?

Radiant heat warms the floor directly, which can lower the wood’s moisture content faster, so humidity management matters even more with in-floor heating. Use engineered wood rated for radiant heat, follow the maximum surface-temperature limit, and hold indoor humidity at 35 to 55 percent to keep movement in check.

7. Is some seasonal movement in a hardwood floor normal?

Yes. All real wood floors expand slightly in humid summers and shrink in dry winters, so minor seasonal gapping and tightening are expected, not defects. The goal is not to eliminate movement but to limit it by keeping humidity stable, which prevents the extreme swings that cause lasting damage.

8. Where should I place a hygrometer?

Place it in your main living area, near the floor and away from vents, radiators, exterior doors, and the humidifier itself, so it reads the air the floor actually sits in. Use a second one on another level if your home has a basement or upstairs, since humidity can differ from floor to floor.

Ask us for a humidity plan when you visit the Saint-Jerome showroom. We will match the tools to your home so your new floor is protected from day one.

450, boul. Roland-Godard, Saint-Jerome, QC | (450) 431-8789 | planchersbellefeuille.com