Laminate

Peaking, Gapping and Bounce in Floating Floors

Diagnosing peaking, gapping and bounce in floating floors, traced back to the expansion, pinning, flatness and environment rules in the makers' instructions.

Updated · 3 min read

Floating floor failures almost always trace back to one of the installation rules: the floor was pinned, the gap was too small, the subfloor wasn't flat, the pad was too soft, or the room left the maker's range. Find which rule was broken and you've found the fix.

Symptoms

Match what you see to where to look first.

Symptom Check first
Peaking or buckling at joints Expansion gap, pinning (trim, cabinets, transitions, door casings), heat and sun
Gaps at ends or sides Joints not fully locked, crooked starter row, broken locks
Bounce, clicking or hollow feel Subfloor flatness, soft or doubled pad, deflection

Peaking and buckling

A floating floor that can't move pushes up.

  • The perimeter gap is required; skip it and the floor can buckle.[1]
  • Pinning: Pergo Extreme must never be glued, nailed or fastened to the subfloor, and cabinets and islands go in first.[2] A point load over 600 lb on a single board can stop the floor from floating.[7]
  • Transitions and trim: moldings must not pinch the flooring against the subfloor, and door trim should be undercut so the floor moves freely.[6]
  • Run length: breaks are required on large areas, and limits vary. Pergo laminate: over 40 ft.[1] Mannington ADURA Max: over 50 ft or 2,500 sq ft.[4] See Floating floor layout.
  • Heat and sun: excessive heat can make the floor expand and buckle.[4] Pergo Extreme's 2019 sheet calls for a 5/8" gap where temperatures exceed 85°F.[8]

Gapping

Most gaps start at installation.

  • Any gap in a joint can compromise the locking system.[3]
  • Check that each joint is fully locked before moving on.[2]
  • Rows should be no more than 3/16" out of straight in 10 ft; a crooked starter row can open side and end gaps later.[7]
  • Broken locks: slide planks apart to disengage them, or the lock can break.[6]

Bounce and hollow feel

Bounce comes from what the floor is sitting on.

  • Flatness limits vary: 3/16" in 10 ft or 1/8" in 6 ft for COREtec and AHF,[3][6] and 3/16" in 10 ft plus 1/32" in 12" for Mannington ADURA Max.[4] See Subfloor flatness.
  • Soft layers: soft underlayment weakens the locking system.[3] See Underlayment for floating floors.
  • Structure: repair creaking subfloors before installing, and check the joists if the subfloor sags.[1]

Temperature and humidity ranges

Every product has its own range; these are examples.

Product Temperature Relative humidity
Pergo laminate 60 to 85°F 35 to 65%[1]
Mannington laminate 65 to 90°F 30 to 65%, for the life of the floor[5]
COREtec Pro 55 to 85°F Not specified[3]

How to fix it

Correct the cause, then the symptom.

  1. Pull the trim and transitions and check the perimeter gap all the way around.
  2. Free any pinch points: nails through the floor, trim pressed down, tight door casings, cabinets set on the floor.
  3. Cut back the flooring where the gap is too small, and undercut door casings 1/16" higher than the flooring plus underlayment.[7]
  4. For gaps, slide rows back together with a tapping block and pull bar, or replace planks with broken locks.
  5. For bounce, take up the affected area, correct flatness or remove the extra pad, and reinstall.
  6. Reinstall trim fastened to the wall only. See Cutting base shoe and quarter round.

When to replace instead of repair

Planks with broken locks or swollen edges won't recover, and distortion doesn't go away over time.[6] Replace them after correcting the cause.

Tools we carry

These help open the gap and reseat the floor.

References

  1. Pergo: Installation essentials (laminate)
  2. Pergo Extreme Uniclic installation
  3. COREtec Pro installation guidelines
  4. Mannington: ADURA Max installation
  5. Mannington: Laminate installation
  6. AHF: Rigid core installation
  7. NWFA: Wood Flooring Installation Guidelines
  8. Pergo Extreme installation (2019 update)

Linked PDF documents are archived copies saved by PreFloor Tools so they stay available if the publisher moves or removes them. Check the publisher's website for the latest revision.

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