Framing Sleeper Floors

You can install laminate, engineered wood, resilient flooring, and many other finished flooring materials directly over a dry concrete slab. However a wooden subfloor helps insulate the flooring from the cold concrete. It also adds a little cushion to the hard surface of the concrete. A wooden subfloor will not cure moisture problems. Moisture that comes up through the slab will ultimately find its way into your finished floor. Cure the moisture problem before you install the floor.

Headroom, especially in a basement, may be at a premium. To make low flooring framing that will conserve headroom, lay pressure-treated 2x4s (sleepers) flat and cover them with 3/4-inch tongue-and-groove OSB underlayment or exterior plywood.

Prepare the slab by vacuuming it, then seal with an asphalt primer and a layer of asphalt mastic. Lay a moisture barrier (6 mil polyethylene is often used) and mark the plastic sheet with a felt marker so you can position the sleepers on 16-inch centers.

Prestart Checklist

Time
About 8 hours for a 10x10 floor

Tools
Circular saw, level, powder-actuated gun, cordless drill

Skills
Measuring and marking, cutting lumber, installing mastic and waterproofing membrane using powder-actuated fasteners

Prep
Clean and repair floor

Materials
Polyethylene membrane, tape, powder-actuated fasteners, shims, screws, 3/4-inch tongue-and-groove OSB underlayment or exterior plywood, pressure-treated 2x4s