Skip to content
(904) 555-0186
  1. Home
  2. Projects
  3. Flooring over a slab

Flooring Over a Concrete Slab

Most houses around Jacksonville are built on a concrete slab, and the slab decides how well any new floor performs.

Jacksonville Flooring Contractors HQ connects you with a local contractor who preps slabs properly.

Here is what that prep should include.

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

Installer pouring self leveling compound over a ground concrete slab before new flooring

Slabs Hold Moisture

Concrete gives off moisture from the ground below, even when the surface feels dry. Trapped under a floor, that moisture can cup wood, open seams in laminate and loosen adhesives.

That is why moisture testing comes before any vinyl, laminate or wood goes down. Newer slabs and homes near the water deserve extra care.

How Slabs Are Tested

Two tests are common. A calcium chloride kit sits on the surface and measures how much moisture comes out over a set time. A relative humidity probe goes into a small hole drilled in the slab and reads moisture inside the concrete.

The probe is generally seen as the more accurate of the two. Either way, the reading gets compared with the limits on the flooring product's data sheet, which differ by product.

Flat Comes Next

Rigid core vinyl plank and laminate can't bend over a hump or into a dip. On a slab, the fix is grinding the high spots and filling low ones with patch or self leveling compound after a primer.

Skipping or rushing this step shows up again and again as the cause of gaps, creaking and lifting. If an installer isn't talking about grinding and leveling, it probably isn't being done.

Barriers and Underlayment

  • Floating floors: a moisture barrier film or an underlayment with one built in, unless the plank's attached pad already includes it.
  • Glue down floors: an adhesive or sealer rated for the slab's moisture reading.
  • Dimpled mats: raised channel mats let air move under the floor. They are more common in basements up north, but the idea is the same: keep the slab's moisture off the flooring.

Doubling up underlayment under a plank with attached pad can void its warranty. Follow that product's install guide.

Small Details on Concrete

Installers often anchor the first and last rows of a floating floor near the seams with temporary masonry screws, so the locking joints can't pop open while the rest goes in. Trim covers the spots.

Where a transition strip meets existing carpet, they should shim and support it before drilling, so the drill doesn't snag and run a carpet fiber.

Best Floors for a Slab

Tile bonds directly to concrete and ignores moisture. Vinyl plank and waterproof laminate float over it well with the right barrier. Engineered wood can be glued or floated. Solid hardwood needs a plywood layer first.

Compare luxury vinyl plank flooring installation, engineered hardwood flooring installation and tile flooring installation.

Want a slab checked and quoted? Send the estimate form or call (904) 555-0186.

Call (904) 555-0186