Cantilever Floor Insulation Detail

In addition to floors other cantilevered architectural features may require insulation.

Cantilever floor insulation detail.

You should only put in fiberglass insulation if you can access the cantilevered floor joist from a basement or crawl space. Fiberglass must be cut precisely to fill in the batts in the floor joists. 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. 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.

I am having a hard time finding details showing the sealnt barriers and insulation for the cantilevered floor. Measure the size of the opening between the floor joists underneath the cantilevered overhang. Cellulose cantilevered floor insulation. 2 cut pieces of 1 inch nonstructural sheathing board or 1 inch rigid foam sheathing to fit inside the.

You can use rigid foam of any thickness on the underside of a cantilevered floor in your climate zone. Of course you need to protect the rigid foam from abuse with a layer of plywood osb or soffit material. When it comes to floor assemblies the stack effect works in your favor lowering rather than increasing the risk of moisture accumulation. 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.

Installing cellulose via the crawl space is fairly simple as it is just blowing the material into the floor joists. 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. Any suggestions would be greatly appreciated.