Flooring guide
Why Are My Flooring Joints Opening?
Learn why flooring joints open in LVP, laminate, hardwood, and engineered floors, including humidity movement, expansion gaps, locking damage, poor acclimation, and fixed objects.
Useful calculators for this guide
What issue are you seeing?
Jump straight to the symptom that most closely matches the floor problem.
Quick answer
Flooring joints usually open because the floor is moving, unsupported, damaged, or reacting to moisture and humidity changes. LVP and laminate joints can open when locking systems are stressed. Hardwood and engineered hardwood can gap from seasonal movement or moisture imbalance.
Start by identifying the flooring type, where the gaps are appearing, whether the floor is floating or glued/nailed, and whether humidity, subfloor movement, or fixed objects are involved.
Troubleshooting flow
Diagnose the problem before choosing a repair
Start with the pattern, check the most likely causes, then decide whether the repair is simple or needs an installer.
Seasonal movement
- Likely symptom
- Gaps change with humidity
- What to check
- Track indoor humidity and whether gaps open or close seasonally.
Unsupported floating floor joints
- Likely symptom
- Gaps near bounce or hollow movement
- What to check
- Check subfloor flatness and support under the joints.
Pinned floating floor
- Likely symptom
- Gaps away from tight trim or fixed objects
- What to check
- Inspect cabinets, islands, transitions, trim, and perimeter space.
Damaged locking edges
- Likely symptom
- Joint will not stay closed
- What to check
- Inspect plank edges before forcing repair or filling.
| Possible cause | Likely symptom | What to check |
|---|---|---|
| Seasonal movement | Gaps change with humidity | Track indoor humidity and whether gaps open or close seasonally. |
| Unsupported floating floor joints | Gaps near bounce or hollow movement | Check subfloor flatness and support under the joints. |
| Pinned floating floor | Gaps away from tight trim or fixed objects | Inspect cabinets, islands, transitions, trim, and perimeter space. |
| Damaged locking edges | Joint will not stay closed | Inspect plank edges before forcing repair or filling. |
What to check first
- Identify the flooring type and whether it is floating, glue-down, nailed, or stapled.
- Map where the joints are opening and whether they are widening.
- Check humidity, moisture history, and recent seasonal changes.
- Look for bounce, clicking, peaking, lifting, or hollow movement near the openings.
When to call a professional
- Joints keep reopening after being closed.
- Gaps are spreading, lifting, or paired with moisture signs.
- Hardwood gaps are wide, uneven, or not seasonal.
- Repair may require lifting planks, replacing damaged boards, or checking moisture.
Floating floor movement concept
Floating floor movement concept
Visual example only. Final layout depends on product requirements, field conditions, and installer judgment.
What joint opening can mean by flooring type
Laminate and floating LVP separation often points to support, locking joint, expansion, or moisture concerns. Tapping planks together may not last if the floor keeps flexing or remains pinned.
Hardwood and engineered hardwood gaps may be seasonal, but wide, uneven, growing, or localized gaps should be checked for moisture imbalance, acclimation, or installation concerns.
Example scenario
A homeowner notices end joints opening in an LVP hallway after cabinets were installed over part of the floating floor. The gaps may be related to a pinned floor and long-run expansion pressure, not just loose planks.
The next step is checking expansion space, fixed objects, and subfloor support before trying to close the joints.
Common mistakes
The biggest mistake is treating the visible symptom as the whole problem. Noise, gaps, peaking, crowning, and moisture concerns usually start with movement, moisture, substrate support, or product-specific installation requirements.
- Forcing joints closed without checking why they opened.
- Filling hardwood gaps before understanding seasonal movement.
- Ignoring fixed cabinets, islands, or transition tracks on floating floors.
- Missing low spots that flex under locking joints.
- Assuming all gaps are installation defects.
Industry References & Further Reading
These resources are useful starting points for checking industry-aligned installation principles. Product instructions and installer field judgment still control the final project details.
People with this problem also investigate
Compare nearby symptoms and jobsite conditions before deciding whether the issue is material, moisture, movement, subfloor, or layout related.