Floor Joist Panning

Used to seal the underside of the floor joist space to create a return air duct.

Floor joist panning.

So far the only option i have found was to use hard pipe. This product is proudly made in the usa using galvanized steel construction for durability and rust prevention. Joist panning lining seems to still be popular. One is the pan joist system a standardized beam and girder system of constant depth formed with prefabricated sheet metal forms.

This panning is constructed with sturdy 30 gauge galvanized steel. A two way version of pan joists called the waffle slab uses prefabricated hollow sheet metal domes to create a grid pattern of voids in a solid floor slab saving. Master flow 16 in. Using floor joists as return ducts by panning can cause leakage because negative pressure in the cavity will draw air from the outside into the cavity through the construction joints of the rim area at the end of the joist cavity.

Galvanized panning is used to seal the underside of a joist space. It can be cut to size to suit a variety of applications. 16 in width is equal to the distance of joist spacing allowing the panning to be nailed or screwed directly into the wood. Still commonly used is the panned floor joist.

It also can be nailed on the bottom of floor joists to convert floor joist cavities to a duct run. I am looking for an alternative to replace joist panning that is easier to seal and better all around. However a have read in a few places that joist panning is difficult to seal and can pull air from unconditioned spaces.