Solid hardwood · Gaps between boards
Why are there gaps between my hardwood floor boards?
Some seasonal gapping is normal in solid hardwood: boards shrink in dry months and close up again when humidity returns. Gaps that are wide, permanent or getting worse point to a moisture or installation problem.
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What usually causes it
- Dry indoor air, such as heating season, Santa Ana winds or desert climates
- Wood installed with too much moisture, which then shrank
- Wide boards, which move more than narrow ones
What you can check yourself
- Notice whether gaps close in humid months
- Measure a few gaps with a coin or card, then compare over time
What an independent inspection checks
- Moisture content of the flooring and the subfloor, mapped across the room
- Room temperature and relative humidity, and how they change by season
- Concrete slab moisture (ASTM F2170 in-situ RH) when the floor is over concrete
- Gap measurements compared with NWFA guidance on normal seasonal movement
Who is responsible?
Normal seasonal gapping is not a defect. Excessive gapping from wet installation can be an installation issue.
Get your hardwood floor inspected
Tell us what you're seeing and we'll explain the next step. We cover every county in Southern California and only inspect. We don't sell or install flooring.