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Handbook: A Floating Insulated Subfloor For Slab On Grade Construction

Five videos about how to install a subfloor over thick insulation without sleepers.
May 13, 2022
Read time: 1 min
Dan Morrison

Typically, a subfloor is installed over floor joists, but for slab-on-grade construction, sometimes a subfloor is installed atop the slab—such as when installing wood flooring. In such a case, it is wise to insulate between the slab and the subflooring. 

The insulation can be rigid foam board or rockwool and usually involves sleepers. In the case of this project, the slab is a slabless slab: compacted gravel and there are no sleepers.

Two layers of subfloor are offset and glued together, forming a floating subfloor over a floating layer of insulation.

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