Polyicynene is an organic material developed from products of the petrochemical industry that has the texture and appearance of angel food cake. The foam is made up of millions of tiny cells filled with air that provide permanent control of air and moisture movement. The product is applied on the building site by a trained and licensed installer and provides a custom insulation that fits into virtually any size of cavity (Figs. 10.1 and 10.2).
The Icynene Insulation System is a two-part system consisting of isocyanate MDI and polyicynene resin. The two liquid components are mixed under heat and pressure in a 1:1 ratio within a spray-gun mixing chamber. Water serves as the foaming agent, reacting with the other components to generate C02, which expands the foam. This eliminates polyurethane’s HCFC-related environmental problems but also means a lower R-value because the cells are filled with air, not a blowing agent. Triggering the gun allows the material to be released to the substrate, similar to spray painting, where it reacts from the mixture and expands to 100 times its liquid size. Within seconds, the foam expands to its full thickness, filling (and sometimes overfilling) the cavity. The labor involved in applying 10" of foam is not a great deal more than in a 2" application, so thicker applications are more cost – effective than thinner ones.
According to the manufacturer, the Icynene Insulation System provides an environmentally safe, complete insulation and air retarder system that windproofs and seals wall, floor, and ceiling cavities against air movement, including spaces around electrical outlets and light fixtures, at baseboards, and behind window and door frames. In fact, the company promotes the Icynene Insulation System for its air-sealing properties as well as for its insulating properties. The foam does not shrink or sag and adheres to most surfaces. Because the foam remains flexible, it expands and contracts with seasonal movement of a building to remain airtight.
The Icynene insulation is noncorrosive. It is neutral, neither acidic nor alkaline, and it cannot support bacterial or fungal growth. Since it is a “breathing” foam, any moisture in the building’s concrete or lumber can escape through the insulation as the building dries out, reportedly eliminating any risk of rot or mildew.
The Icynene insulation is sprayed in place by a professionally trained and licensed contractor after electrical and plumbing services are in place. Gypsum wallboard typically is installed directly over the Icynene insulation 10 minutes after application. According to the manufacturer, building wrap, polyethylene, taping, foaming, and caulking are eliminated because the foam works as an air retarder. (A separate vapor retarder is indicated for regions with cold winters.) Designers and builders should still verify this design requirement with local experts based on climate behavior and use of poly icynene.
Icynene, Inc., has developed a second formulation that can be foamed, by pouring, into closed cavities. The product expands from bottom to top to fill the cavity. A minimum of two pours, or lifts, are typically recommended. The cavity-fill product has a slightly greater density with an R-value of 4 per inch.