The company offers SIPs in three panel types: StructureWall, CurtainWall, and PineClad. StructureWall panels, which replace studs and rafters, are twice as strong as a 2x4 wall, according to the manufacturer. CurtainWall panels, ideal for timber-frame or metal-frame buildings, include an interior skin of gypsum for finishing. PineClad panels offer the benefits of StructureWall but with an interior finish of tongue-and-groove pine. Foam cores are available in expanded polystyrene or polyisocyanurate. 802-254-3435. www.winterpanel.com.