Floating floors

What makes floating hardwood floors different from traditional hardwood flooring is that such floors aren't glued or nailed to the wood subfloor or concrete slab. The planks are attached to each other, and sit on top of the subfloor or sound barrier.

The floor is installed with a small expansion gap at all edges, to allow for some natural expansion and contraction due to the seasons. The expansion gaps are never seen, they are covered by molding or shoe trim, and door thresholds (see diagram at right). (Source: BC Hardwood)

Specifications for Installing Radiant Heated Wood Floors over Slab-on Grade

Over traditional concrete radiant slabs at least 4 inches deep, use either a floating hardwood floor or install subflooring and nail on 3/4-inch strip flooring. The subflooring can consist of two layers of 1/2-inch plywood floating over the slab (see “Installing Over Concrete,” page 168), or a single-layer 3/4-inch subfloor nailed to the slab with powder-actuated fasteners. Because it is thicker, the floating subfloor (Figure 5-15) will take slightly longer to heat up, but it does not risk puncturing the hydronic tubing. (Source: InspectAPedia)