March 4, 2026
DO I NEED TO REPLACE MY SUBFLOOR BEFORE NEW FLOORING?
The honest answer? Almost never. Subfloors usually need repair, levelling, or moisture remediation — full replacement is rare.
WHEN REPLACEMENT IS REQUIRED
Water damage that has rotted the subfloor (soft, spongy, dark stains). Severe sagging from joist failure. Damage from a previous failed install (heavy adhesive, deep gouges). These are real but uncommon.
WHEN REPAIR IS ENOUGH
Squeaks: screw the existing subfloor down to the joists. Small low spots: self-levelling compound. Holes: patch with plywood. These are part of a normal install.
WHEN LEVELLING IS ENOUGH
Most subfloors aren't flat enough for modern flooring (especially large-format tile and rigid LVP). Self-levelling compound poured to manufacturer tolerance fixes 90% of cases.
BEWARE THE UPSELL
Some installers quote subfloor replacement when they really mean "I haven't looked carefully." Get a second opinion if you're quoted full subfloor replacement on a house under 30 years old without obvious water damage.