Gaps in hardwood floors show up every Toronto winter — here's why seasonal humidity causes them, how to close them, and when a gap actually needs a professional fix.
A Toronto homeowner's guide to seasonal gaps and how to keep them under control
Every winter, Toronto homeowners notice the same thing: thin gaps opening up between the boards of their hardwood floor. It can be alarming if you've just invested in a beautiful floor — but in most cases these winter gaps are normal, seasonal, and fixable. This guide explains why gaps in hardwood floors appear when the weather turns cold, how to close them, and how to tell the difference between a harmless seasonal gap and one that needs a professional.
Why Winter Causes Gaps in Hardwood Floors
Wood is a natural material that constantly reacts to the moisture in the air around it. In summer, humid air makes each board absorb moisture and expand slightly; in winter, the air dries out and the boards release moisture and shrink. When every board in a room shrinks a fraction of a millimetre, those tiny movements add up across the floor and show as gaps between the planks.
In Toronto the effect is amplified because our winters are a double hit: the outdoor air is already cold and dry, and running forced-air heating dries the indoor air even further. Indoor humidity in a heated GTA home can easily fall below 30% in January — well under the level wood prefers — which is exactly why gaps tend to appear in the coldest months and close again by spring.
Are Winter Gaps Normal? How to Tell
For solid hardwood, seasonal gapping is normal and expected. The key question is whether the gaps are seasonal (they open in winter and close in summer) or permanent (they stay year-round).
A quick way to check: note where the gaps are and how wide they are in mid-winter, then look again in summer. If they've narrowed significantly or disappeared, they're seasonal and nothing is wrong with your floor. Gaps that persist through the humid months, keep widening year over year, or come with cupping, cracking, or loose boards point to something more than seasonal movement — and that's when it's worth a professional look.
How to Prevent and Close Winter Gaps
The single most effective fix is not filling the gaps — it's managing your indoor humidity. Wood floors are happiest between roughly 35% and 55% relative humidity, and holding that range keeps seasonal movement small.
Here's the practical approach:
- Measure first. Put an inexpensive hygrometer in the rooms with hardwood so you know your actual humidity, rather than guessing.
- Add moisture in winter. If you're consistently below 35%, run a whole-home humidifier on your furnace or use portable humidifiers in the affected rooms. Raise the level gradually and watch the floor over the following weeks — well-humidified air often narrows or closes the gaps on its own.
- Keep it stable. Sudden swings are harder on wood than a steady, slightly-dry winter. Aim for consistency rather than perfection.
- Don't fill seasonal gaps in winter. It's tempting, but filler or rope pushed into a winter gap gets squeezed out — or worse, contributes to buckling — when the boards expand again in summer. Save any permanent filling for a professional to assess in the humid season.
Maintaining stable humidity does more than close gaps; it also protects your floor's finish and helps keep your manufacturer warranty valid. Our guide to maintaining the beauty of your hardwood flooring covers year-round care in more detail.
Engineered vs. Solid Hardwood: Why Stability Matters
If seasonal gaps bother you, the type of wood floor you choose makes a real difference. Solid hardwood is a single piece of wood, so it moves the most with humidity. Engineered hardwood is built from a real-wood veneer over a cross-layered plywood core, and that construction resists expansion and contraction far better — which means noticeably less seasonal gapping in our climate.
That stability is a big reason engineered hardwood has become the default choice for Toronto homes, condos, and basements. If you're planning a new floor and want to minimize winter movement, our guide to engineered hardwood for your Toronto home explains how wide planks, veneers, and installation methods work together for a stable, long-lasting result.
When Gaps Need a Professional Fix
Some gaps aren't seasonal, and no humidifier will fix them. It's time to bring in a professional when you see:
- Gaps that stay wide open through summer as well as winter.
- Gaps that grow larger each year rather than cycling with the seasons.
- Cupping (edges higher than the centre of the board), crowning, or boards lifting.
- Cracked, splintered, or loose planks around the gaps.
These can point to a subfloor moisture problem, an installation issue such as too little acclimation or an inadequate expansion gap, or age-related wear that calls for board repair or refinishing. A professional can identify the cause, repair or replace affected boards, and — where appropriate — permanently fill stable gaps during the humid season. If your floor is showing damage beyond simple seasonal movement, our guide to restoring damaged hardwood flooring walks through the options.
Frequently Asked Questions
Are gaps in hardwood floors in winter normal? Yes. Seasonal gaps that open in the dry winter months and close again as humidity rises in spring and summer are completely normal for solid hardwood. It's a sign the wood is doing what natural wood does — reacting to the moisture in the air.
What humidity level stops hardwood floor gaps? Keeping indoor relative humidity between about 35% and 55% year-round minimizes seasonal movement. A hygrometer to measure and a humidifier to add winter moisture are the two tools that make the biggest difference in Toronto homes.
Should I fill the gaps in my hardwood floor? Not seasonal ones, and not in winter. Filler forced into a winter gap tends to pop out or cause pressure when the boards expand in summer. Only permanent, year-round gaps should be filled — and that's best assessed by a professional in the humid season.
Does engineered hardwood get winter gaps too? Much less than solid hardwood. Its cross-layered core resists moisture-driven movement, so gaps are smaller and far less common — which is why it's a popular choice for our climate. Stable indoor humidity still helps.
My gaps don't close in summer — what's wrong? Year-round gaps usually mean more than seasonal movement — possibly a subfloor moisture issue, an installation problem, or age. It's worth having the floor assessed so the underlying cause is fixed, not just the symptom.
A Quick Winter Checklist for Your Hardwood Floor
A few small habits keep seasonal movement to a minimum and your floor looking its best through the cold months:
- Put a hygrometer in each hardwood room and check it weekly through winter.
- Aim for 35–55% relative humidity — run a humidifier whenever you drop below that range.
- Raise humidity gradually, not all at once, and give the floor a few weeks to respond.
- Keep the temperature steady — big day-to-night swings dry the air unevenly.
- Watch for problem signs — cupping, loose boards, or gaps that don't close in summer mean it's time for a professional look.
- Resist filling gaps in winter — wait for the humid season and a professional assessment.
- Keep entry mats at the doors — road salt and grit tracked in over a Toronto winter are abrasive and wear down the finish that helps the wood hold its moisture.
Do these and most winters will pass with nothing more than a few hairline gaps that quietly close come spring — no filler, no stress, and a floor that's ready for the humid months ahead.
Keep Your Hardwood Floor Looking Its Best Year-Round
Winter gaps in a hardwood floor are usually just your floor responding to Toronto's dry, heated air — manage your indoor humidity and most of them close on their own. But if gaps persist through summer, keep growing, or come with cupping or loose boards, it's worth a professional assessment before the problem spreads.
FloorSure is a fully insured, WSIB-covered flooring specialist serving Toronto and the GTA, and every installation is backed by our 1-year workmanship warranty. We offer a wide range of materials, styles, and installation options, and the right solution varies with your home, your subfloor, and the condition of your floor — so we're happy to assess your space and recommend the best approach. Explore our hardwood flooring services, or call or message us on WhatsApp at +1 (437) 988-0524 to book a free on-site consultation.
