Laminate flooring is designed to be a floating floor that may be installed over virtually any type of sub floor. By “floating”, we mean that it doesn’t need to be nailed or glued to the subfloor. One of the biggest benefits to installing a floating floor is the limited amount of floor prep needed. The word used was limited prep, not no floor prep. The need to remove old floor coverings and adhesive, many of which have asbestos content, can be a real hassle. On large commercial jobs the cost of hiring an asbestos abatement company and bead blasting the concrete may be feasible, but on most residential jobs this is cost prohibitive. Floating the floor eliminates the need for removal, in most cases.

Manufacturers recommend that the floor be flat to within 3/16” in 10 feet. These measurements are consistent with most other types of floor coverings. On floating floors, vertical movement needs to be kept to a minimum. I often hear that it is difficult to determine if prep is needed when carpet is on the floor. Most subfloors are going to require some kind of prep regardless if they are floating or not.

Checking for flatness

Using a laser level is fast and efficient. Shoot a line to a target with a ¼” scale marked on the face. Sliding the target along the floor will indicate areas that require leveling. If the line moves up on the target the floor has a low spot, if the line moves down, the floor has a high spot. Using a pencil,

mark the areas high and low areas. You can also use a straight edge. Lay the straight edge on the floor. 3 quarters stacked equal 3/16″. You can also use a spacer. Anywhere that you can slide the spacer or quarters under the straight edge need fixing.

Fixing the floor

In many cases I prefer to sand or grind down the high spots as opposed to bring the rest of the floor up to meet the high spots. On concrete floors, I use a grinder with a diamond wheel with a dust

shroud and a vacuum attached. For low spots, fill with a Portland based patching compound.

IMPORTANT NOTES:

• Remember, new concrete must cure for a minimum of 60 days before being tested for moisture.
• Cover all concrete sub floors with manufacturers approved vapor retarder or 2 in 1 foam like FloorMuffler
• Wood sub floors must be structurally sound and deflection free.
  • Use a sander or portable planer to take down high areas. The seams on OSB are always an issue. Remember to set the nails before using the plane.
  • Fill in low spots, use patching compounds that are intended for this use. Check the instructions for thickness limitations.