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Subfloor Repair

The subfloor is what your floor sits on, and you usually only see it once the old flooring is up.

Jacksonville Flooring Contractors HQ connects you with a local contractor who can repair it before new flooring goes down.

Skipping this step is the fastest way to ruin a new floor.

Call (904) 555-0186Talk to a local flooring contractor

Section of rotted plywood subfloor cut out between floor joists, ready for new plywood

Slab and humidity check

On a slab home, the "subfloor" is the concrete. Repair there means grinding high spots, filling low ones and sealing cracks, not replacing plywood. Raised wood floors over crawl spaces are where rot and soft spots show up most.

Signs Something Is Wrong Underneath

  • A soft or spongy spot when you step on it.
  • A dip you can feel near a toilet, tub, dishwasher or exterior door.
  • Squeaks or clicks that get worse over time.
  • Musty smell, staining or mold at the edge of the old floor.

Water damage, mold and soft or holed sections are often only found after old flooring or cabinets come out. A good quote says how surprises like that will be priced.

How a Proper Repair Goes

  1. Find the joists, usually from the panel seams. They are commonly spaced sixteen inches apart.
  2. Check for pipes and wiring under the cut line. Cutting into either turns a small repair into a big one.
  3. Cut the damaged section out back to sound wood over the joists.
  4. Add blocking or sister framing where the joists need support.
  5. Fit new subfloor, commonly three quarter inch plywood, with a small gap at the edges.
  6. Fix the cause of the water. Otherwise the repair is temporary.

Not Every Stain Means Rot

Some staining is old and cosmetic. If the wood is still hard and dry, a stain blocking primer may be all it needs. A screwdriver test tells a lot: sound wood resists, rotten wood gives.

The point is to know which you have, rather than assume the worst or cover it up.

Why It Can't Wait

Subfloor problems grow. Mold spreads, framing weakens and new flooring laid over a soft spot cracks, clicks or separates early. It's one of the few places where spending a bit more up front clearly saves money.

Before any new floor, every old nail and screw should sit flush, and the surface should be checked with a long level. Low spots get floor patch, not leftover thinset. On a slab, see flooring over a concrete slab.

Permits and Pricing

Replacing floor covering alone usually needs no permit, but structural framing or subfloor work may. Check with the City of Jacksonville building office, or your county, for your job.

Subfloor repair is often priced per square foot, typically around one to three dollars for the repair area, and changes with access and damage.

It belongs on the quote as its own line. See how to compare flooring quotes and water damaged floor replacement.

Got a soft spot? Send the estimate form or call (904) 555-0186.

Call (904) 555-0186