Subfloor preparation can include cleaning, removing protrusions, fastening loose plywood, treating accessible squeaks, scraping adhesive, grinding high areas, patching low areas, smoothing joints, applying primer, installing approved underlayment, or using levelling products. The required work depends on the new flooring and the substrate.
Preparation is defined by the new floor
A substrate that is acceptable below carpet may not be smooth enough for glue-down vinyl. A surface that supports laminate may not be rigid enough for tile. Large-format tile, floating planks, fastened hardwood, and bonded resilient flooring use different requirements.
Concrete preparation
Concrete work can involve cleaning, old-adhesive review, scraping, grinding, patching, crack observation, moisture requirements, low areas, floor drains, intentional slope, curing, and compatible primers or levelling materials. Active water entry is not corrected by installing a new floor.
Plywood and wood-subfloor preparation
Wood assemblies can involve protruding fasteners, loose sheets, damaged edges, seams, squeaks, patches, thickness, joist movement, previous underlayment, or unsuitable repairs. Accessible fastening may reduce some movement, but structural concerns remain separate work.
Flat is not the same as level
A basement floor may slope toward a drain while remaining reasonably flat. Another room may appear level but contain local waves. The goal should reflect the product requirements, room function, stairs, doors, drains, and final elevations.
What a useful scope should say
The estimate should identify the area, method, preparation material, assumed thickness, grinding or patching, cure requirements, and what is excluded. “Floor prep as needed” is too vague when the existing floor has not yet been removed.
Frequently asked questions
Is floor levelling always required?
No. It is required only where the substrate and selected flooring need correction, and the appropriate method depends on the actual conditions.
Can underlayment hide an uneven floor?
Underlayment may serve approved cushioning, sound, or vapour functions, but it does not normally replace required flatness correction.
Who repairs structural subfloor problems?
Structural repairs may require a qualified renovation, carpentry, engineering, or other specialist scope outside ordinary flooring preparation.