Will spray foam insulation make a house less drafty and less noisy?

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Yes and yes. Spray foam insulation, properly known as closed-cell spray polyurethane foam or SPF (no relation to your sunscreen!), has made such a mark on the insulation industry that there’s an entire magazine devoted to it. Proponents say there’s no better material for sealing your home from unwanted air and moisture, which in turn saves on utility bills and blocks out pests, airborne pollutants and allergens. In more and more new homes, it’s replacing the rigid foam insulation boards that were the norm.

In fact, when spray foam is used in a building envelope, it can outperform fiberglass insulation and create a superior air barrier. If it eliminates the need for an expensive building wrap or an additional vapor barrier, you start saving money during construction as well as when as you go to heat and cool your home.In some cases spray foam can be applied to the inside of roofs and under floors in existing homes and, of course, it can be used in a new addition.

Why is SPF becoming the new standard? Because it does more than insulate—it can protect your home in a variety of ways.

The Benefits Of Spray Foam Insulation

  • An air and moisture barrier. Moisture can’t soak its way through polyurethane spray foam’s closed cell structure the way it can fiberglass and cellulose. SPF acts as an effective air barrier that puts an end to energy lost due to air infiltration—drafts through walls sockets, windows and doorways that can account for up to 40 percent of a home’s energy loss. By sealing the stud and wall cavities from end to end and top to bottom, SPF closes all the gaps.
  • One step results. Spray foam seals and insulates in one step, and it stays in place because of its adhesive qualities. Though often used as an air-sealing treatment step before filling an attic with blow-in insulation for instance, used in larger amounts, it can eliminate the need for a second type of insulation.
  • More comfortable, less cost. The R value (a sign of insulation’s ability to retain heat) is higher in spray foam than in traditional products because it provides a no-leak seal and is very dense. That means your home is more comfortable and less expensive to heat in the winter and cool in the summer. Another bonus: Demands on HVAC equipment won’t be as great.
  • Adding strength to structure. SPF is permanent, seamless and virtually sag-proof, so it adds to your building’s stability. Once the foam cures, it's not going to settle or shift.
  • A mold, dust and pollen barrier. Mold and mildew can’t get a foothold because of spray foam’s moisture barrier. Closing up gaps means that other nuisances, like dust, pollen and other irritants and allergens, can’t get into your home through cracks.
  • A sound barrier. SPF also has sound reduction properties to make your home acoustically tighter, with less noise able to travel from room to room.

Finding A Pro

Look for an experienced professional who knows how to handle spray foam since there are different formulas that expand at different rates. An incorrect application around a window frame or doorjamb can make it the door or window inoperable. Also, excess, called “overspray,” can be messy to clean up and is wasteful. The products must also be used within a specific temperature range, so this is a job for a seasoned professional.

Photo courtesy of National Association of Certified Home Inspectors