spray foam insulation 12/2011

Spray Foam insulation has been specified by our office for both residential and commercial projects with successful results. Although cost is always a concern, we prefer spray foam insulation over standard fiberglass batt insulation because of its comprehensive insulating and air sealing capabilities, along with a proven long term durability record.



What is Spray Foam insulation?

Foam insulation is a polyurethane that is sprayed into the wall and ceiling cavities, which expands and cures within minutes. As it expands in the cavity, it fills all of the voids and crevices, creating a continuous air barrier. This air barrier substantially reduces the outside/inside air movement, which historically results in tremendous heat loss and water vapor movement. Spray foam insulation can be specified in two ways; open cell or closed cell, depending on final desired performance capabilities required. Open cell insulation has an R-Value of 4/inch and allows a small amount of vapor movement, while closed cell insulation has an R-Value of 7/inch and allows less than 1.0 perm of vapor movement, which classifies it a Class II vapor retardant. Many of the spray foam insulation products in the marketplace are Energy Star Certified. Spray foam is sold under brand names such as Icynene, Certainteed, and Corbond.


Why Spray Foam insulation? There are several advantages to installing spray foam insulation:

  • Reduced Energy Use:Spray foam has an air sealing capability that allows furnaces and air conditioners to run more efficiently, instead of having to adjust based upon typical building envelope air leakage. With as much as 30% of house air leakage being directly attributed to poorly sealed and insulated walls, floors, and ceilings, the installation of foam insulation has the potential to reduce heating and cooling energy costs. And because the foam serves as an effective air barrier, incorporating a well designed ventilation system that facilitates sufficient fresh air movement is a critical consideration, which can be achieved by an engineered mechanical system with adequate fresh air intakes.
  • Better Indoor Air Quality:Spray foam insulation will minimize the infiltration of airborne irritants such as allergens, drafts, or humidity. Tests have proven that spray foam insulation is not a food source for mold.
  • Moisture Control:99% of moisture in your home is born from air infiltration. In order to manage moisture in a home, the air flow must be minimized. Once spayed into the cavity, the foam adheres to the structure and expands into hard to reach areas, such as around electrical outlets and ceiling lights. We typically specify closed cell foam in the ceiling cavities, which eliminates the need of venting attic and rafter bays, keeping all potential condensate out of the roof/attic.
  • Sound Control:As result of the thousands of microscopic air cavities,spray foam insulation has substantial acoustical attenuation properties, effectively reduce the amount of noise from plumbing lines, general room to room ambient noise, and from exterior to interior.
  • Durability:Spray foam Insulation is flexible and will move with the building’s natural shifts over time. And unlike Batt insulation, foam will not settle or sag once it is place, which results in a wall or ceiling assembly that has a consistent R-value.

Cost Analysis:

Spray foam insulation cost, including installation varies from $4/sqft for open cell to $7/sqft for closed cell. Standard Fiberglass Batt insulation including installation costs an average of $1/ sqft. In a typical 2,500 sqft home, insulating the roof and the exterior walls, the total is insulate would be approximately 6,400 sqft. The cost to insulate with Batt insulation would be $6,400. To install a hybrid spray foam assembly, with Open cell foam in the exterior walls, and Closed cell in the roof framing, the total cost is $34,632. To install Closed cell throughout, the total cost would be $44,832. Combined with the previously mentioned energy savings and air sealing capabilities, many of our clients find the upfront added cost for spray foam reasonable when considering all of the added value and benefits.