True or False: SIPs have two layers of closed-cell spray foam sandwiched between building materials.

Structural Insulated Panels (SIPs) typically consist of a core of rigid foam insulation sandwiched between two structural facings, which are usually made of oriented strand board (OSB) or plywood. The foam used in SIPs is often expanded polystyrene (EPS), extruded polystyrene (XPS), or polyurethane, rather than closed-cell spray foam. Closed-cell spray foam may be used in insulation applications but is not the standard for SIPs. Therefore, the statement claiming that SIPs have two layers of closed-cell spray foam sandwiched between building materials is not accurate, making the answer false. This distinction is crucial for understanding the composition and insulation properties of SIPs in building construction.