Optimization of polystyrene foam core sandwich panels for self-supported roof applications

Energy efficiency in residential building applications is an important aspect in reducing greenhouse gas emissions such as carbon dioxide. Thus, significant emphasis is now being placed on the building enclosure and the importance of having a continuous boundary of insulation between the interior conditioned space and the external environment. Structural insulated panels (SIP's) comprised of an expanded polystyrene (EPS) bead foam core sandwiched between oriented strand board (OSB) facings have been used predominantly in exterior wall applications to date due to deficiencies in meeting load-bearing requirements for structural roof panel applications.;An alternative approach combines OSB facings with structural lath frames and orthotropic extruded polystyrene (XPS) foam core to render composite sandwich panels that satisfy allowable spans for self-supported installation. Foam constitutive material properties and finite element (FE) models of composite roof panels were constructed to investigate the effects of facing, lath and foam core characteristics on panel deflection and constituent strength factor of safety considerations. Such FE models were then used in conjunction with HEEDS automated design software to optimize the geometric configuration of various roof sandwich panels.