Common questions about Spray Foam Insulation
There are a lot of common questions and misconceptions about spray foam insulation. Here you can find answers to many of the questions and concerns that are commonly voiced when talking about spray foam insulation.
How does Spray Foam Insulation work?
Insulation works by slowing the movement of heat from a hot space to one that is cooler. Heat moves in three ways: radiation, conduction and convection.
Radiation is heat transfer through electromagnetic light waves that we can't see. You feel radiant heat from a burning fire or from sunlight streaming into a window that strikes your body. In the winter, warm objects in your home can radiate heat directly through glass to the outdoors unless you have special Low-E glass that blocks this infrared energy.
Conduction heat transfer happens when heat moves through an object. The heat excites the molecules in a heated object and these molecules excite the ones next to them. The closer packed the molecules are in an object, the more rapid the heat transfer. A great example of conduction is a cool spoon that is placed in a hot bowl of soup. Within a few minutes the end of the spoon not immersed in the soup will be warm or hot to the touch.
Convection heat transfer happens when a fluid such as air or water gets heated by a hot object that touches the air or water. Forced air furnaces are great examples of convection heat as the air moving over the heat exchanger gets warm and then passes that warmth to objects it touches once it is in the room.
You feel convective drafts in a room in winter as well. If you stand in front of a large pane of glass that is not insulated glass, you can feel a cold draft. That is actually air that has lost or transferred its heat against the glass and the warm air that has not turned cold falls towards the ground.
Insulation stops these different movements of heat transfer. The insulation absorbs the heat and slows its movement.
Does spray foam insulation have building code approvals?
Yes. Spray foam insulation is approved by the Residential and Commercial building codes.
What is the difference between vented & unvented attics?
Unvented attics use air-impermeable insulation on the underside of the roof deck as a barrier to prevent condensation of moisture. Vented attics allow hot and/or moist air to escape to the exterior by air flow.
What is the difference between open cell and closed cell spray foam?
Open cell:
a) Low density (.5lb per cubic foot).
b) Expands about 100 times its original volume when applied.
c) Forms a semi rigid/flexible insulation.
d) R-value is between R3.4 to R3.9 per inch.
e) Forms an excellent air barrier.
f) A good soundproofing material
Closed cell:
a) Medium density (2lbs per cubic foot).
b) Expands about 40 times its original volume when applied
c) Forms a rigid insulation (adds structural strength).
d) R-value is R6.0 or higher.
e) Forms an excellent air barrier.
f) Applied at 2” or more, closed cell SPF is a vapor retarder material.
How does spray foam insulation save money when compared to fiberglass or cellulose?
While the initial cost of installing SPF maybe higher than other traditional insulation, homeowners are able to save more money per month to more than make up for this difference. SPF can reduce heating/cooling costs (compared to traditional insulations) by up to 50%. SPF can also save money by way of a reduction in the required sizing of the HVAC unit.
Will spray foam insulation "settle" or fall from the walls or ceiling over time?
Spray foam insulation adheres to the substrate and will not settle or fall out of the walls or ceiling.
How long does spray foam last?
Indefinitely. As an inert, long lasting polymer, residential and/or commercial structures are a great places for spray foam insulation.
Is spray foam considered an air barrier?
Yes. Spray foam will stop air infiltration in commercial/residential buildings. This will also keep out moist/humid air and dust/pollen. Fiberglass batts and loose cellulose will not stop air infiltration allowing dust, pollen and moisture into a home/building.
Does spray foam insulation aid in the growth of mold?
Spray foam insulation offers no food value; therefore it does not support bacteria or fungal growth. It also does not retain water, making it an unappealing environment for fungal spores.
How is spray foam installed?
SPF is a two component liquid that’s sprayed in place by a trained professional applicator. The two liquids, heated under high pressure, mix at the spray gun reacting with each other causing the liquid to expand rapidly and cure as a rigid/semi-rigid foam.
How does spray foam insulation control moisture movement and condensation?
Moisture damage within a building envelope is mainly the result of warm moist inside air being exchanged with the cold dry outside air with your walls. As moisture in the air condenses, it forms dew within the insulation. Because spray foam insulation is air sealing, this moisture movement and condensation do not occur.
What is the flame spread and smoke development of spray foam insulation?
Spray foam has a flame spread of <25 and smoke development of <450. With these results, spray foam is a Class 1 rated material. This is the highest rating an insulation product can receive for residential and commercial applications.