How to level a Concrete Slab Floor for Hardwood Flooring

By Mark J. Donovan

If you plan on installing hardwood flooring on a concrete slab you first need to make sure the concrete slab is level. If it is not, then depending upon how unlevel it is you either first need to apply a leveling compound, or build a shimmed subfloor.

Regardless if the concrete slab floor is level you should always build a wood subfloor for the hardwood flooring to rest on. The subfloor should be framed with pressure treated 2x4s or other wood material such that water wicking up from the concrete slab will not destroy the subfloor over time.

As you build the subfloor you can adjust its height with shims so that you create a completely level floor. Just remember to start the construction of the subfloor at the highest point in the room.