Symptoms
- Visible gap under the baseboard along the floor
- Gap wider in some spots than others
- Dust or drafts coming through the gap
- More noticeable after a dry season
Likely causes
- CommonNormal seasonal wood movement in flooringFloors expand and contract with humidity, sometimes pulling slightly away from the baseboard.
- CommonHouse settling over timeGradual settling can open small gaps between the floor and wall trim.
- PossibleBaseboard installed with a gap for flooring expansion originallySome floating floors intentionally leave a small expansion gap that's simply visible if quarter round wasn't added.
- Less commonBaseboard itself warping or pulling away from the wallHumidity or age can occasionally warp the baseboard rather than the floor moving.
What to do
- Measure the gap's width at its largest point to decide on the best trim solution.
- For a small, consistent gap, caulking along the top of the floor where it meets the baseboard can close it cleanly, especially on hard flooring.
- For a floating floor (laminate, engineered wood, vinyl plank) with an intentional expansion gap, install quarter round or shoe molding along the baseboard rather than caulking directly to the floor, which needs room to move.
- Nail the quarter round into the baseboard only, not into the floor, so the floor can still expand and contract freely underneath it.
- Caulk the top of the quarter round against the baseboard for a finished look, but leave the bottom against the floor uncaulked for flooring types that need to move.
- Paint or stain the new trim to match the existing baseboard.
- For a gap caused by a warped baseboard rather than floor movement, that section of baseboard may need to be reattached or replaced instead.
Tools and parts
- Caulk gun
- Miter saw or hand miter box
- Finish nailer or hammer
Quarter round moldingSearch: “quarter round shoe molding trim”
When to call a pro
Call a carpenter or flooring installer if gaps are large, widespread, or you suspect settling rather than normal seasonal movement.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.