Evaluation of structural insulated panels for National Building Code compliance

Volume 17, Number 1, March 2012

Researchers at NRC are developing technical criteria to assist manufacturers of Structural Insulated Panels (SIPs) to secure evaluation of their products for compliance with the National Building Code of Canada. Evaluations are carried out by the NRC Canadian Construction Materials Centre (NRC-CCMC), with tests conducted by third-party laboratories based on protocols contained in a technical guide.

SIPs are produced by sandwiching a layer of insulating foam between two wood-based panels

SIPs are produced by sandwiching a layer of insulating foam between two wood-based panels such as oriented strand board (OSB). The panels provide the primary structural role, while the foam provides shear and insulating properties. A SIP product that incorporates studs along the vertical edges of the panels to ensure structural performance has undergone a successful evaluation. There is, however, no protocol enabling the evaluation of SIPs without studs. The latter type of SIP relies on the OSB panels to support the loads associated with the walls and roofs of a house, with the insulating foam providing shear resistance and preventing panel deflections.

In order to write a technical guide for SIPs without structural studs in the panels, issues such as the long-term structural performance of the SIPs, the potential for creep, and the durability of the bond between the foam and the OSB panels all need to be understood. NRC is undertaking a new research project to provide the needed information. The research team will then work with NRC-CCMC evaluation officers to develop the needed structural and durability protocols for incorporation into a technical guide. The research team is currently seeking input from manufacturers and construction practitioners.

This work is expected to advance the adoption of SIP technology. Both academic studies and demonstration houses have shown that houses built using SIPs have higher insulating values than standard wood-frame construction. Industry studies suggest that SIPs may also be better at controlling air leakage. Other potential advantages include a faster rate of construction and a reduction in construction waste since SIPs are pre-manufactured to architectural and engineering designs.

For more information

Interested parties can contact project manager, Jon Makar at 613-993-3797 or jon.makar@nrc-cnrc.gc.ca.