insulating floor over concrete slab
Zone 2A single story modern ranch house construction. Part of the house slab is cantilevered with a recess (6″) planned to add insulation underneath wooden floors. My plan was to use 4″ Toprock DD (which I have left over from the roof) + 1/2″ rigid xps foam to place underneath the 3/4″ Advantech and 3/4″ wooden flooring.
Is Toprock DD adequate for floor insulation? Should the insulation be secured to the concrete, should the OSB be secured? Or can these be cut to fit snugly, making the whole construct stable? Thank you for your advice.