Every winter our hardwood develops small gaps between boards and then they close up in summer — is that just normal seasonal movement here or a sign of bad install?

This is completely normal seasonal movement - exactly what you should expect with hardwood flooring in Ottawa's climate. Wood is a natural material that expands and contracts with humidity changes, and our dramatic seasonal swings make this movement quite noticeable.

During Ottawa winters, indoor humidity typically drops to 20-30% due to heating systems, causing hardwood boards to shrink and create small gaps between planks. In summer, humidity rises to 50-60% or higher, and the boards expand back to close those gaps. This cycle happens every year and is actually a sign that your hardwood is responding naturally to environmental conditions.

The key indicators this is normal movement rather than installation issues include gaps that appear consistently across the floor (not just in isolated areas), gaps that are relatively uniform in size (typically 1-2mm), and most importantly, that they close up again when humidity returns. If you had installation problems, you'd likely see permanent gaps, cupping, crowning, or gaps that keep getting worse over time.

Ottawa's climate is particularly challenging for hardwood because we can swing from very dry winter air to humid summers. Most quality installations account for this by leaving proper expansion gaps around the perimeter and using appropriate fastening techniques. The gaps you're seeing between boards are the wood's way of accommodating these changes without buckling or warping.

To minimize the seasonal movement, consider running a humidifier during winter months to keep indoor humidity around 35-45%. This won't eliminate the movement entirely, but it can reduce the size of the gaps. If the gaps seem unusually large (more than 3-4mm) or don't close up in summer, that could indicate an installation or moisture issue worth having evaluated.

For peace of mind about your specific situation, a flooring contractor can assess whether the movement is within normal ranges for your wood species and installation method.