Crawl Space Insulation - Benefits of Polyurethane Spray Foam

Crawl Space Insulation usually consists of batt insulation installed between the floor joists over a crawl space foundation. 

Problems associated with this installation technique include incomplete thermal barriers from obstructions such as wiring and plumbing, ductwork, and narrow or wide joist spacing.  Batts are often compressed during installation due to the use of wire insulation hangers.  Open web floor trusses create additional problems in that the open webs create pathways for air to move around the batts.  During the summer, warm humid air can flow around the crawl space insulation batts in and create condensation, mold and decay problems in the floor system.  In my opinion, open web floor trusses are impossible to adequately insulate with batts.
 
Spray foam circumvents floor and crawl space insulation problems through its ability to completely fill voids and open spaces.  Areas around wiring and plumbing as well as open webs of floor trusses can be completely filled, resulting in a complete, essentially uniform thermal barrier on the floor.  Spray foam will also create an effective air flow retarder layer on the floor, which will reduce the house air by crawl space air.
 
Crawl space insulation with spray foam insulation offers a superior insulation product that overcomes several disadvantages of other insulation products.  Spray foam can provide a more uniform, consistent thermal barrier as well as provide air flow retarder functions. To best obtain spray foam’s potential benefits, and overcome it’s higher initial costs, spray foam should be used in a systems approach to creating a better building.

In a roof application, spray foam will increase the structure’s ability to handle high winds as well as bring the attic into the conditioned space.  A roof application of spray foam will reduce infiltration and reduce ceiling heat transfer and duct losses. Wall and floor applications will also create better thermal and air barriers, and make better use of engineered products.  Spray foam insulation can result in less conductive, convective and radiant heat transfer, lower infiltration rates, less duct losses, a more structurally sound building and can result in significantly smaller-sized heating and cooling systems and better comfort levels for the occupants.