Cantilever Floor Insulation Detail

You can use rigid foam of any thickness on the underside of a cantilevered floor in your climate zone.

Cantilever floor insulation detail.

Of course you need to protect the rigid foam from abuse with a layer of plywood osb or soffit material. 2 cut pieces of 1 inch nonstructural sheathing board or 1 inch rigid foam sheathing to fit inside the. Install insulation without misalignments compressions gaps or voids to fill the cantilever floor cavity making full contact with the top bottom and sides of a cantilevered floor cavity cover the bottom of the insulated cantilever floor cavities with a rigid weather resistant solid blocking material such as plywood or house siding. I am working on a project where the main floor is cantilevered over the concrete foundation wall.

Fiberglass must be cut precisely to fill in the batts in the floor joists. If the floor is over a garage and has not already been insulated however it is recommended that each joist bay be filled with insulation. You should only put in fiberglass insulation if you can access the cantilevered floor joist from a basement or crawl space. Installing cellulose via the crawl space is fairly simple as it is just blowing the material into the floor joists.

Usually only the cantilevered portion of the floor needs to be insulated. In addition to floors other cantilevered architectural features may require insulation. Cellulose insulation can be installed in the cantilever floor joists two ways through access from the crawl space or by drilling holes through the bottom of the overhang. The details i do have show a cantilever over a wood frame wall not a concrete foundation wall.

Any suggestions would be greatly appreciated. Cellulose cantilevered floor insulation. This material has a few drawbacks as it still allows some airflow through the floor and is known to trap allergens and moisture which can leave.