Flooring and indoor humidity in Canada

What indoor humidity does my floor need?

Keep indoor relative humidity between 35 and 55 percent to protect wood flooring, which is what almost every hardwood manufacturer specifies in its warranty. The challenge is that Canadian winters push indoor humidity far below that: 20 to 25 percent is typical in southern Ontario, and 15 percent or lower in Calgary, Winnipeg, Saskatoon, Edmonton and the territories. At those levels solid hardwood shrinks and visible gaps open between boards every winter, closing again in summer. A furnace humidifier costing $500 to $1,500 installed is what makes solid hardwood viable in most of Canada. If you cannot or will not maintain humidity, choose engineered hardwood, laminate or rigid-core vinyl, all of which tolerate dry air with far less movement.

Why wood moves

Wood is hygroscopic: it absorbs moisture from humid air and releases it to dry air, expanding and contracting across the grain as it does. A solid oak board 5 inches wide can change width by more than a millimetre between a humid August and a dry January. Multiply that across a room and the gaps become obvious.

Regional reality

Coastal British Columbia and the Maritimes have mild, stable indoor humidity and are the kindest climates in Canada for solid wood. Southern Ontario and Quebec see moderate swings. The Prairies, northern Ontario and the territories are genuinely hostile, with sustained indoor humidity below 20 percent for months.

Humidification options

A furnace-mounted bypass or steam humidifier serves a whole house and costs $500 to $1,500 installed, and it is the only practical solution for a forced-air home. Portable units help a single room. Homes with hydronic or electric baseboard heat need portable or standalone systems, which makes solid hardwood harder to justify in them.

Acclimatisation before installation

Flooring must reach equilibrium with the home before it is fixed in place. Two to five days in the room, boxes opened, at normal living temperature and humidity. Installing wood straight off a cold truck in February is a leading cause of gapping and buckling, and it voids most warranties.

Expansion gaps

Every floating floor and every wood floor needs a gap at the perimeter, typically 10 to 12mm, hidden by the baseboard. Skipping it causes buckling when the floor expands in summer. In long runs over about 8 metres, an intermediate expansion joint may also be required.

Common questions

What humidity should I keep my house at in winter?

Aim for 35 to 40 percent. Going much higher in very cold weather causes condensation on windows and inside walls, which creates its own problems. Thirty-five percent is a reasonable compromise between protecting a wood floor and avoiding condensation damage.

My hardwood gaps every winter. Is it defective?

Almost certainly not. Seasonal gapping is normal wood behaviour in a dry climate, and boards typically close again in summer. It becomes a defect only if boards cup, crown, crack or separate permanently. Adding humidification reduces it substantially.

Does vinyl flooring care about humidity?

Not meaningfully. Rigid-core vinyl responds to temperature rather than humidity, and even then very little. It is the correct recommendation for any home where maintaining winter humidity is impractical, which includes most homes in the Prairies and the North.

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