Thick layers of cementitious floor patch ... was coming up with the boards.
Failure of Three Layers of Poor Subfloor Preparations

acclamation, adhesive, boards, Bostik's Best, carpet, cementitious, chipping hammers, concrete foundation, concrete substrate, cracks, crunching, debris, deep-fill applications, demo equipment, demolition, dining room, discolored, dust, engineered hardwood, failure, fissures, FL, floor patch, floor patching compound, flooring inspection, floors, Florida, foreclosure, foyer, hall, hardwood, home, house, install, installation, installer, laminate, layers, leveling compound, levelness, mildew, moisture content, moisture damage, new homeowner, office/library, old wood, paint residue, primer, radius, remediation, removal process, replaced, residential, rotten, scimcoats, scrape, scraper, screen, slab, sub-floor, substrate, sunken living room, unlevel, wet, wood floors, wood manufacturer, Zephyrhills