Why are there gaps between my baseboard and the floor?

Gaps between your baseboard and floor are typically caused by house settling, seasonal wood movement, or installation issues - and they're more common than you might think in Ottawa homes.

The most frequent culprit is natural house settling, especially in newer homes (under 5 years old) or after major renovations. As your home's foundation and framing adjust to Ottawa's freeze-thaw cycles, slight shifts can create gaps where perfectly fitted baseboards once sat flush. This is particularly noticeable in homes built on clay soil, which is common throughout the Ottawa Valley.

Seasonal wood movement is another major factor in our climate. Ottawa's dramatic humidity swings - from dry winter air (often below 30% humidity) to humid summers - cause wood flooring to expand and contract significantly. Hardwood floors can shrink up to 1/4 inch across a 12-foot span during winter, pulling away from baseboards that remain stationary. If you notice gaps appearing in winter and closing in summer, this is likely the cause.

Installation issues can also create persistent gaps. If baseboards were installed before flooring (common in new construction), or if the flooring wasn't properly acclimated to your home's conditions before installation, gaps are almost inevitable. Sometimes contractors leave intentional gaps for expansion, but these should be minimal and consistent.

For minor gaps (under 1/4 inch), you can use paintable caulk or quarter-round molding to cover them. However, if gaps are large, uneven, or appearing suddenly throughout your home, this might indicate a more serious settling issue that should be evaluated by a professional.

Ottawa's clay soil makes foundation movement more likely than in other regions, so don't ignore widespread gapping. If you're seeing gaps appear along with other signs like doors sticking or cracks in drywall, it's worth having a contractor assess whether there's underlying structural movement.

For persistent or concerning gaps, especially in finished basements where moisture and settling are common issues, a professional evaluation can determine whether this is normal settling or something requiring attention.