Building Science and Your New Home
Controls air infiltration
One of the country’s most critical home energy problems is air infiltration. United States Government Energy Labs
estimate that air infiltration wastes up to 40% of every home heating and cooling dollars. Unfortunately, most
residential buildings were constructed before the size of the problem, the ease of the solution were so widely
known. Read more about how the “Homes have to Breath” rule is properly applied.
Spray Polyurethane Foams have been used as a high-performance insulation material for more than 30 years.
However, their multi-functional role as insulating air and vapor retarders has increased in new and retrofit
construction markets. Investigations by building scientists have shown air leakage to be the main problem
responsible for poor energy conservation performance in buildings.
People call it “air infiltration” but, technically, its unwanted, uncontrolled airflow through the house, moving in or
out of the structure. For example, in cold weather, the heated air inside the house flows out. Frigid outside air and
moisture leak in – rooms feel drafty.
This uncontrolled air disrupts the temperature, air pressure and humidity of the living space, in any weather. The
heating and cooling system has to work harder to maintain your family’s comfort. Energy is wasted and that
causes higher utility bills.
Air infiltration is caused by leaks around windows and doors, and by the spaces, joints, voids and cracks hidden
inside the structure. Hidden is the problem. Once the house is finished, gaps become invisible but they are there.
Air penetrates the building shell in one location, flows through interior cavities and emerges at a different location.
Typically, this uncontrolled air travels through the house inside walls and ceilings, under baseboards, and along
hidden pathways in the plumbing and electrical system. Even the best-built houses have seams and gaps that
permit air infiltration.
Unlike other home insulations, the sealing quality of SPF eliminates the need for wind-inhibiting building wraps,
tapes and caulking and, depending on the type of design construction, even sheathing can be eliminated.
SPF has many advantages that the designer can exploit when specifying an air barrier for the building envelope.
Its inherent fully adhered and structural nature lends itself to fulfilling the requirements of an air barrier.
A home that is well-insulated and protected from moisture intrusion through effective air
infiltration control...
• reduces the usage of fossil fuels for energy
• reduces the CO2 emissions that are damaging the environment, AND
• saves the homeowner money.
The U.S. Department of Commerce brochure NISTIR
4821, Envelope Design Guidelines for Federal Office
Buildings: Thermal Integrity and Airtightness, which was
prepared as a guideline for the General Services
Administration, recognizes and states that...
Spray Polyurethane Foam alone
“CAN provide an
air and water-tight barrier."
Reduces/eliminates Convection Currents Within The Walls
Intrusion of air into the stud wall cavity causes convection (movement of warm air to the top of the cavity and cold
to the bottom). After the insulation is installed, there should not be any air circulation from one side of the stud
space to the other. Any cracks or breaks in the system will reduce the effectiveness of the insulation. Unlike other
insulations such as fiber, which permit air movement, SPF stops air infiltration and reduces convection.
Minimizes Infestation
SPF has no nutritional value that would attract insects or other pests.
Minimizes Thermal Bridging
Different components of building construction have differing thermal resistances factors. This can produce cold
areas that lead to condensation inside the walls. SPF covers the bridges on all sides, greatly reducing the
transmission of heat or cold. Fully-adhered SPF replaces the need for adhesives or numerous mechanical
fasteners that penetrate the substrate and decrease insulation efficiency.
Controls Condensation
Many homes now are built tighter and with greater insulation than ever before. However, this can mean that
moisture from cooking, laundry and showers can be trapped in attics and other places where it can lead to
wood rot, peeling paint, and deteriorating roofing and ceiling materials. In turn, that can affect the insulation
value of commonly used home insulation materials. Used to insulate, SPF insulation systems control both
heat build-up and condensation, resulting in a cooler attic in warmer environments and a dryer attic in cold
climates. For the homeowner, that means comfort, energy conservation and structural stability.
Sprayed-in-place polyurethane foam insulation adheres to, conforms to, and fills in all the little nooks
and crannies in your home's walls, floors, and ceilings and forms a tight insulating barrier that stops air
leakage. The result is that your home is more comfortable and costs less to heat and cool.
Please contact me at onlyfoam@sbcglobal.net or 616-241-6227 for assistance in wading through all of
the decisions required while building a new home. Precisely matching the heating and cooling system to
the actual load of your home is critical. It is not your job to educate the contractors working on your
new home. Our systems approach will provide you a significant return on your investment that will
keep paying you back for years to come.
Bruce Gilman
Advanced Insulation Technology, LLC
4495 Clay Ave. SW Wyoming MI 49548