Engineered hardwood · Hollow spots
Why does my glued-down engineered floor sound hollow?
Hollow spots in a glued floor usually mean the adhesive didn't fully bond to the boards or the subfloor. The usual causes are poor adhesive coverage, an uneven subfloor, or moisture affecting the adhesive.
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What usually causes it
- Insufficient adhesive transfer or the wrong trowel
- Subfloor not flat
- Slab moisture weakening the adhesive
What you can check yourself
- Tap the floor and mark the hollow areas with painter's tape
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
- Adhesive coverage at test locations
- Subfloor flatness
Who is responsible?
Typically installation or site moisture rather than the flooring itself.
Get your engineered floor inspected
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