Spray Foam Insulation in Yonkers, NY

Spray foam insulation is a two-part liquid that reacts and expands as it is sprayed, filling the cavity and bonding to wood, masonry and sheathing. That bond is the point. Fiberglass and cellulose slow heat, but air moves around and through them; foam stops the air at the same time. In a Yonkers house built before the war, where air leaks are often a bigger problem than missing insulation, that makes foam the right tool in a handful of specific places.

Open cell

Open-cell foam weighs about half a pound per cubic foot and expands a great deal, which lets it fill irregular rafter bays and wrap around wiring and blocking. HomeGuide lists it at R-3.5 to R-3.7 per inch. It is a strong air barrier and it quiets sound, but water vapor can pass through it, so it needs the right conditions on the cold side. We use it most for the underside of the roof deck over finished attic rooms and for open stud walls during a gut renovation.

Closed cell

Closed-cell foam is about two pounds per cubic foot, rigid when cured, and rated R-5 to R-7 per inch by HomeGuide. At normal thickness it acts as a vapor retarder and does not absorb water. That is why it goes on rim joists, foundation walls, the ceiling of a garage under a bedroom, and roof slopes too shallow to fit vent channels plus enough fluffy insulation to reach the target R-value. It costs more per square foot, so we put it where its density matters.

When foam is not the answer

On a wide-open attic floor with good access, sealing the top plates and penetrations and then blowing in deep cellulose or fiberglass usually reaches R-49 for less money. In a closed plaster wall, standard spray foam cannot be applied at all; dense-pack cellulose or an injection foam goes in through small holes instead. We will tell you when a cheaper option makes more sense.

Safety and the day of the job

While foam is sprayed and curing, the area is closed off and ventilated and people and pets stay out. HomeGuide advises being out of the house for at least 24 hours with many products; we tell you the exact time for the product we use. Foam inside living space must be covered by a thermal barrier such as drywall, and foam in attics and crawl spaces needs an ignition barrier or a product rated for that use. We plan for that in the quote.