Sleeper

The Full Picture

Sleepers are rows of lumber laid flat over a concrete slab or on the ground, and a subfloor or finished floor is fastened to them. They are used to create a nailing surface over a slab, to raise a floor to meet another elevation, to build a wood floor in a gym or stage, and to support decks on grade. The space between sleepers may stay open, be filled with insulation, or hold a moisture barrier, so sleeper floors often come with a wider assembly of vapor barrier, insulation and subfloor.

On drawings, a sleeper floor appears in a floor assembly detail or a section, not on the plan, and the spec gives the lumber size, treatment, spacing and fasteners. Wood in contact with concrete is commonly preservative-treated, and the specification states whether it is required. The framing plan or the architectural floor plan gives the area. Where a sleeper floor meets a slab edge, door threshold or a change in level, details show how the ends are handled.

The unit is linear feet of sleeper. Divide the dimension across the rows by the spacing, round up, add one for the last row, then multiply by the length of each row. Convert to board feet from the nominal size if lumber is priced that way (a 2x4 is 2 x 4 / 12 board feet per linear foot), or to pieces from stock lengths. Waste varies with how many short pieces the layout creates, and it should be stated as a judgment. Fasteners, adhesive, shims and any insulation between the rows are separate items.

Pricing mistakes include forgetting the treated lumber premium, omitting shims for a slab that is not flat, and leaving out the subfloor, which is its own line in SF. The height of a sleeper floor also changes the quantities elsewhere, for example door thresholds, stair risers and wall base. Some crews lay a second layer of sleepers or add blocking at the edges, which should be read from the detail.