Why do hardwood floors gap in winter in New Brunswick homes?

Hardwood floors gap in winter in New Brunswick homes because forced-air heating systems dramatically reduce indoor humidity, causing the wood to lose moisture and shrink across its width. This is the single most common hardwood flooring complaint in the province, and it is a direct result of NB's Maritime climate pattern rather than a defect in the flooring or installation.

Wood is a hygroscopic material — it constantly absorbs and releases moisture to reach equilibrium with the surrounding air. During NB's heating season from October through April, furnaces and heat pumps push indoor relative humidity down to 20-30%, well below the 35-55% range that hardwood needs to remain dimensionally stable. At 25% RH, a 3-1/4 inch red oak plank can lose enough moisture to shrink by 1-2mm across its width. Multiply that across an entire floor and the accumulated gaps become very visible — sometimes wide enough to see the subfloor or trap debris.

Northern NB communities like Bathurst, Edmundston, and Campbellton experience the most severe winter gapping because their heating seasons are longer and more intense. The longer your furnace runs, the drier your indoor air becomes, and the wider those gaps grow. Homes with older, less air-tight building envelopes lose humidity even faster than newer construction, which compounds the issue in NB's abundant older housing stock.

The good news is that seasonal gapping is usually reversible. When spring and summer arrive and Maritime humidity rises, the wood reabsorbs moisture and swells back toward its original dimensions, closing most or all of the gaps. This annual cycle of gapping and closing is normal behaviour for solid hardwood in NB — it is not a sign of poor installation, and attempting to fill seasonal gaps with putty or caulk usually makes things worse because the filler prevents the planks from expanding back together cleanly.

The solution is humidity control, not floor repair. A whole-home humidifier connected to your forced-air system is the most effective tool for maintaining 35-45% indoor relative humidity throughout NB's heating season. These units cost $300-$800 installed and pay for themselves by protecting not just your hardwood floors but also your woodwork, furniture, and respiratory comfort. Portable room humidifiers can supplement in smaller spaces but struggle to manage humidity across an entire home.

If you are choosing new hardwood flooring for an NB home, engineered hardwood is significantly more resistant to seasonal gapping than solid hardwood. Its cross-layered plywood core restricts width-wise expansion and contraction, keeping gaps minimal even without perfect humidity control. Engineered hardwood runs $6-$14/sq ft fully installed versus $8-$14/sq ft for solid, and it is the recommended wood flooring choice for NB's demanding humidity cycle.

Proper acclimation before installation also reduces gapping severity. Hardwood must sit in your home for 5-10 days before installation so it reaches moisture equilibrium with your indoor environment. Installing wood straight from a cold delivery truck or unheated warehouse — a common mistake in NB — means the wood has not yet adjusted to your home's conditions, leading to excessive movement after installation.

If your hardwood gaps are persistent, wider than 2-3mm, or do not close in summer, that may indicate a more significant moisture imbalance or installation issue worth having a professional assess. New Brunswick Flooring can connect you with an experienced hardwood flooring professional for an evaluation.

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Looking for experienced contractors? The New Brunswick Construction Network connects homeowners with qualified professionals:

• 3Tone Construction Ltd
• Gionetterenovations
• M&L Commercial and residential services
• Forever Epoxy Inc
• First united design & construction inc.