The Most Important Floor Is the One You Never See
When a floor fails early — tile that cracks, planks that gap, carpet that ripples — the finish material almost never did anything wrong. The subfloor under it did. Seventy years of Valley heat cycles, seismic shakes, and settling soil have left most Van Nuys slabs and wood subfloors with dips, cracks, and soft spots that new flooring can't hide and won't survive.
That's why every flooring job we take starts below the surface: measure flatness, probe for soft wood, test for moisture, and fix what's wrong before anything pretty goes down. It's the least visible work we do and the most decisive.
AUTHORITY LINK TODO: subfloor-repair-and-preparationPrep isn't a line item to trim from a bid. It's the difference between a floor that's flat in year ten and a callback in year one.
What Post-War Slabs Throw at Us
Most of Van Nuys sits on slab-on-grade concrete poured during the 1940s–70s building boom — often without the vapor barriers modern code requires. The usual findings on homes near Vanowen Street and Lake Balboa: settled corners that leave a room out of level, shrinkage cracks that telegraph through tile, old glue and cutback adhesive from long-gone floors, and moisture wicking up where exterior drainage has failed.
The fixes are well-established. High spots get diamond-ground. Low areas get self-leveling compound poured to spec. Moving cracks get isolation membranes so the new floor floats over them instead of breaking with them. And when a moisture meter says the slab is wet, a mitigation coating or vapor-barrier underlayment goes down before any finish floor does.
None of it is exotic — it just has to actually be done, which is exactly the step rushed installs skip.
Wood Subfloors: Squeaks, Soft Spots, and Sag
Raised-foundation homes have their own list. Squeaks mean the subfloor has worked loose from the joists — fixed by screwing it back down, not by hoping the new carpet muffles it. Soft spots mean water or termites got to the wood; those sections get cut out and replaced with new material, and anything structural underneath gets flagged honestly.
Bounce and sag between joists show up in older additions where spacing was generous; an underlayment layer stiffens the field so tile and rigid floors don't flex and crack. We also check what decades of previous owners left behind — double and triple layers of old flooring stacked up, each one stealing door clearance and hiding the real condition underneath. All of that comes out during flooring tearout and disposal so repairs happen on the actual subfloor, not on top of history.
Prep Matched to the Floor Going Down
Different finish floors demand different prep, and we scope to the destination. Tile is the strictest: rigid, flat, deflection-free, with crack isolation over any slab movement. Floating floors — laminate and LVP — need flatness above all, roughly 3/16 inch over 10 feet, plus a vapor barrier on concrete. Hardwood wants dry wood or a properly prepared slab with the right underlayment. Carpet is the most forgiving, but pad and tack strip still need sound material to bite into.
That's also why subfloor work is folded into our flooring quotes rather than sold as a mystery extra: the measurement happens at the estimate, the scope is written down, and the price you approve includes the floor you'll never see along with the one you will.
Every flooring project we run through our Van Nuys flooring services starts at this layer — because that's where floors actually succeed or fail.
Get a free subfloor assessment
Tell us what your floor is doing — squeaks, cracks, slopes — and our licensed team will find the cause and write you a free estimate. CSLB License #1160251. No cost, no obligation.
Van Nuys General Contractor ADU & Remodeling LLC is a licensed California contractor — CSLB License #1160251. We build ADUs, additions and remodels across Van Nuys and the San Fernando Valley, and every project is permitted and inspected through the city.
Frequently Asked Questions
How do I know if my subfloor needs repair?
The floor above tells you. Squeaks and bounce point to loose or soft wood subfloor. Cracked tile and grout lines, gaps opening between planks, or a rolling feel underfoot usually mean the slab or subfloor has moved. If your old flooring failed early, the odds are good the subfloor was the reason — and putting a new floor over the same problem repeats it.
What's under most Van Nuys floors — slab or wood?
Mostly concrete slab. The homes built across Van Nuys in the 1940s–70s boom sit largely on slab-on-grade foundations, with raised wood subfloors showing up in some older and hillside-adjacent properties. Each has its own failure modes: slabs settle and crack, wood subfloors loosen, squeak, and develop soft spots.
How flat does a subfloor have to be for new flooring?
The common spec for floating floors like LVP and laminate is about 3/16 inch of variation over a 10-foot span; tile is even less forgiving. That's flatter than most 70-year-old Valley slabs sit today. Grinding high spots and pouring self-leveling compound over low areas is how a settled slab gets brought back to spec.
Can you fix a subfloor without replacing the whole thing?
Usually, yes. Wood subfloors get refastened to the joists to kill squeaks, and damaged sections get cut out and replaced individually rather than wholesale. Slabs get crack repair, grinding, and leveling compound. Full replacement only enters the conversation when moisture or termites have gone through large areas — and we'll show you exactly what we found before that call gets made.
How does slab moisture get handled?
First it gets measured, not guessed. High readings on a Van Nuys slab are common near old plumbing runs and poor exterior drainage. Depending on the number and the finish floor going down, the fix ranges from a vapor-barrier underlayment to a roll-applied moisture mitigation coating. Solving it costs far less than replacing a buckled floor a year later.
How long does subfloor prep add to a flooring job?
Typically a day or two for routine leveling and repairs, folded into the flooring schedule. Self-leveling compound needs overnight cure before floors go over it. Bigger structural repairs take longer, but those get scoped and priced before work starts — never discovered as a surprise invoice mid-job.