Slab Insulation Retrofit
I have been hired to remodel a basement addition that was built on an existing slab. When the plumbers cut out some of the slab, we realized that there is only 1 inch of rigid insulation beneath the 4 inch concrete slab. The clients don’t want a cold floor, so we plan on adding rigid on top of the slab. The plan is for one inch of rigid on top of the concrete topped with 3/4 plywood as a sub floor. The exterior sliding door was installed to accommodate this plan. The clients haven’t decided finish flooring material yet but it will probably be some kind of engineered wood thinner than 3/4 inch.
My question is simple. There is no plan for sleepers since the height at the threshold won’t allow for it. How would I adhere the rigid to the concrete and how shall I adhere the plywood to the rigid without having sleepers to nail into? Its a small space, 250 square feet. Also, if i taped the rigid (unfortunately XPS) would this be a proper moisture barrier?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part