SIPs, sometimes known as stress skin panels, are made of an insulating foam core with OSB (oriented strand board) bonded to either side. There are three types of foam cores – EPS (expanded polystyrene), XPS (extruded polystyrene), and urethane (either polyisocyanurate or polyurethane), ranging in R-Values from 13 to 40 (R-value refers to a materials ability to resist transferring heat), far above conventional wall construction with fiberglass or cellulose insulation.

Panels are typically installed vertically on the home walls. Panel connections are fastened with splines or cams and then expanding foam insulation is sprayed directly into the remaining space, sealing the connection and creating a continuous thermal insulating wall for the home. (In a timber frame or post and beam home, the panels are wrapped around the exterior of the timber frame.)

Panel wall R-Values differ according to…