Dow Styrofoam Insulation R Value. I ve written several posts about how to insulation basement walls in which i promote the use of foam board insulation as the first line of defense against moisture and mold. With an r 5 value per inch the 2 in. 2 in x 4 ft x 8 ft.
Because of this i often get questions about which type of foam board insulation to use and what r values these products provide. Phenolic foam spray insulation.
4 8 7 21.
Very good air bypass leak sealing properties. Very good air bypass leak sealing properties. Because rigid foam plastic insulation products are not all aged in accordance with the same standards it is useful to publish comparison r value data. R value determined by astm c518.
