What Is SPC Floor Gaps Between Planks?
SPC (Stone Plastic Composite) flooring is marketed as dimensionally stable and waterproof — and it is, on the surface. But SPC still expands and contracts with temperature changes. When the floor contracts in cooler conditions, the locking joints are placed under tension. If the locking mechanism is compromised — by manufacturing defect, subfloor irregularity, or inadequate installation — joints pull apart, creating visible gaps.
Unlike wood flooring, where seasonal gaps may open and close with humidity changes, SPC gaps do not self-correct. Once a locking joint has failed, the gap remains unless the planks are manually re-engaged. And if the cause persists, re-engaged joints will fail again.
In Southern California, the temperature differential between air-conditioned interiors and sun-heated floor surfaces is significant. A floor that expands during the day and contracts at night experiences daily thermal cycling that stresses locking joints over time — particularly in rooms with south or west-facing windows.
What Causes SPC Floor Gaps Between Planks?
Thermal Contraction
SPC contracts when cooled. In air-conditioned homes, particularly at night, the floor contracts and locking joints are placed under tension. If joints are already marginal from installation, the tension pulls them apart. This is common in rooms with temperature cycling.
Subfloor Irregularities
SPC installed over subfloor exceeding 3/16 inch in 10 feet flatness tolerance rocks across high spots. This movement stresses locking joints at the high point, eventually causing them to unlatch and create gaps.
Inadequate Expansion Gaps
Without manufacturer-specified expansion gaps at all perimeters, thermal expansion creates compressive stress that can damage locking joints. When the floor later contracts, the damaged joints pull apart — creating gaps that the damaged locking system cannot close.
Manufacturing Defect in Locking Profile
Some SPC products have undersized, improperly formed, or brittle locking profiles that do not retain under normal thermal cycling. These cases require forensic analysis and may warrant manufacturer warranty claims.
Improper Installation Engagement
Click-lock planks must be engaged at the correct angle and fully seated. Planks that are tapped together without proper engagement, or forced at the wrong angle, may appear locked but separate under the first thermal cycle.
Symptoms to Look For
- Visible gaps between planks at joints
- Gaps that are consistent and do not close over time
- Gaps concentrated in areas with temperature cycling or sun exposure
- Raised or tented edges adjacent to gaps
- Planks that rock or feel loose at gap locations
- Gaps appearing progressively over weeks or months
What an Inspector Checks
When to Call an Inspector
Contact a certified flooring inspector when:
• Gaps are appearing in a floor less than 2 years old
• Multiple gaps are developing across the field
• The installer or manufacturer disputes the cause
• Documentation is needed for a warranty claim
• An insurance or legal dispute is involved
Our Inspection Process
Frequently Asked Questions
Will SPC floor gaps close on their own?
Unlike wood flooring where seasonal gaps may close with humidity changes, SPC gaps do not self-correct. Once a locking joint has failed, the gap remains unless the planks are manually re-engaged. If the cause (subfloor irregularity, thermal stress, defective locking profile) is not corrected, re-engaged joints will fail again.
Is SPC floor gapping an installation or product problem?
Most SPC gapping is caused by installation deficiencies — inadequate expansion gaps, non-compliant subfloor flatness, or improper engagement technique. However, some cases involve genuine manufacturing defects in the locking profile. A certified inspection distinguishes between the two, which is essential for warranty and liability determination.
Can gapped SPC planks be pushed back together?
If the locking mechanism is undamaged, planks can sometimes be re-engaged by a professional. However, if the lock tabs are broken, cracked, or deformed, those planks require replacement. In widespread gapping, full removal and reinstallation with correct installation practices is typically required.
Related Flooring Issues
SPC / Rigid Core
SPC (Stone Plastic Composite) and rigid core flooring develops separating or open joints when thermal expansion forces exceed the locking mechanism's capacity — typically caused by inadequate expansion gaps or extreme heat exposure.
Learn moreVinyl / LVP
Vinyl floor buckling — where planks or sheets lift dramatically off the subfloor — is caused by thermal expansion without adequate room, moisture beneath the floor, or adhesive failure in glue-down systems.
Learn moreVinyl / LVP
Click-lock flooring comes apart when locking mechanisms fail — typically from thermal expansion stress, subfloor irregularities, inadequate expansion gaps, or manufacturing defects in the locking profile.
Learn moreVinyl / LVP
Clicking, popping, crackling, or creaking noises in vinyl flooring are caused by subfloor irregularities, thermal expansion movement, loose locking joints, or debris beneath the floor. Some noise is normal, but new or worsening sounds may indicate installation deficiency.
Learn more