Tripolymer Foam insulation has an R-value of 4.6 per inch at 75°F, 5.0 per inch at 0°F, and 4.8 per inch at 32°F. The manufacturer reports that there is no thermal degradation or reduction in R-value over time.
Few, if any, limitations exist for residential use of this foam. The manufacturer does warn that it should not be used against surfaces with temperatures in excess of 212°F for prolonged periods of time.
Figure 10.4 Tripolymer foam insulation. (C. P. Chemical Co., Inc.)
The foam will not support compressive loads, nor should it be used for flotation (such as floating docks) or applied underground without adequate protection.
Some users have reported a certain amount of shrinkage over time, which degrades its thermal performance. Independent testing conducted by MacMillan Research, Ltd., examined a sample of foam and found that it showed no shrinkage in the accelerated aging test. After 6 days under such conditions, a loss in weight of 4.7 percent was experienced, and no discoloration was apparent. (The 6 days in incubation is the approximate equivalent of 2 years in actual use.)12 These results seem to contradict earlier observations of shrinkage, sometimes of up to V4" away from the studs.13 С. P. Chemical Company reported that the only objectionable shrinkage usually is associated with improper equipment use. Typically, shrinkage of V8" in a wall cavity is the maximum shrinkage to be expected.