Can You Glue Flooring to Sealed Concrete?

Moisture

• Sealing a concrete floor before installing any type of additional flooring, including tile, carpet and wood, is recommended to prevent moisture from being wicked through the subfloor into the new flooring. This works both ways -- if an accidental spill were to occur on a carpet, the moisture would seep through the fibers and into the concrete, where it might stay and cause mildew problems. Moisture wicked from unsealed concrete can cause warping, rotting, splitting, mold and mildew in your new flooring.

Water Test

• Some sealers wear out over time. There's a simple test that will tell you whether your concrete floor is properly sealed. Pour a small amount of water over the concrete floor. If the water beads up and stays on the surface, the floor is still sealed. If the water is absorbed into the floor after 15 seconds or so, the floor will need to be resealed. Test different areas all over the floor to see if there are any weak points in the seal.

Cracks

• If there are any cracks, chips or dings in the floor, these will all need to be patched up before you can reseal the concrete and install the new flooring. If the floor's seal is otherwise intact and passes the water test, you will need to strip the floor before patching the damage -- you can do this with special solvents for removing concrete floor sealers or with a sander fitted with concrete sanding pad. Once stripped, patch the damage with concrete caulk and a trowel or putty knife.

Resealing the Floor

• Although many concrete sealing products will do the trick for sealing away moisture, look for products that are specifically called "moisture barriers." This is the type of concrete sealer you need if you plan on installing different flooring, such as carpet, tile and hardwood panels, over the concrete subfloor. Application instructions vary by product, but most of them are simply rolled on using a paint roller. Multiple applications may be necessary to ensure full coverage.