Article taken from Bob Vila's dotCOM dreamHOME

Icynene Furthers Efficiency in dotCOM dreamHOME

When the time came to cap off the thermal envelope with attic insulation, Icynene's spray-applied insulating foam met the home's mission for comfort, environmental health, energy efficiency, and environmentally conscious design.

First and foremost, Icynene is an effective insulator with an R-value rating of 3.6 per inch and a 2-part foam that expands to fill all cracks and voids. Unlike fiberglass batt insulation, Icynene doesn't need support from the framing, or leave gaps if the stud or rafter bays are spaced too far apart. There's no stuffing into nooks and crannies, no fussy cutting and patching around vent pipes, can lights, wiring, or other complicated elements in the home's walls and ceilings. Icynene adheres to framing and sheathing, and creates an airtight seal throughout the assembly. And, unlike loose or blown-in insulation, Icynene will not settle or blow around: Once it's there, it's there to stay.

The rated R-value for insulation is usually an exaggeration, since voids, gaps, and air infiltration create thermal losses once installed. In a house with a lot of ceiling lights, fans, and other things sticking up through the ceiling, it's hard to insulate the attic floor effectively using fiber insulation, says dotCOM dreamHOME builder Paul Trudeau. You almost never see it done correctly. With Icynene, there are no gaps or voids, so the R-value you buy is the R-value you get.

Using Icynene allowed Trudeau to skip insulating the attic floor entirely. Instead, he had the material spray-applied to the underside of the roof deck. Even though the truss chords are only 2 x 6 members, we could spray on enough insulation to get close to an R-40 roof, says Paul. The best thing is, we brought the entire heating and cooling system inside the conditioned space. Typically, builders locate the furnace and air condition in the attic space, then ventilate that space to the outdoors. They're actually using some of the energy to heat and cool an outdoor space. By insulating the roof plane with Icynene, any heat losses generated in the attic space are kept within the thermal envelope of the house, eliminating that source of waste.

Building this airtight shell did mean making some adjustments, notes Trudeau. We have to install a direct-vent furnace, he explains. "You can't draw the combustion air for heating from the attic in the usual way, because that space is sealed up too tight. We need to bring that air directly from outdoors." The combined energy efficiency from the Icynene roof and Polysteel walls reduces the home's total heating and cooling needs sharply. "We can use a smaller heating and cooling system to meet the need," Trudeau says of the payback.

Sealed combustion appliances are part of an air-quality agenda with Icynene. "Fiber insulations can be irritating to a lot of people, " Trudeau says. "When air ducts run through the attic, that stuff can spread throughout the house. Icynene takes a few days to cure, but after that it's inert. There won't be any fumes or fibers floating around the building." Icynene uses no ozone-depleting CFC propellants to expand itself, either. The two-part foam expands by an internal chemical reaction that produces nothing more sinister than steam and carbon dioxide.

Information on Icynene products and distributors is available online at


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