Structural insulated panels for housing: failure modes upon accelerated aging

Abstract Structural insulated panels (SIPs) with skins of oriented strand boards (OSB) are increasingly used to build energy efficient dwellings. SIPs are sandwich-like construction products where stress-bearing facer panels are located on both sides of a core of rigid insulation. The lack of knowledge of SIPs amongst home builders and the lack of public data on engineering properties and durability of OSB-SIPs currently limit their use. This is particularly the case in Canada, where the National Building Code of Canada requires that new construction products demonstrate similar service lives to traditional materials. The National Research Council of Canada, in collaboration with suppliers of SIPs and SIP components and Alberta Innovates, have recently addressed issues related to the performance and durability of SIPs for the Canadian construction market. The goal of the work was to develop a basic laboratory programme for the accelerated aging of SIP and help to establish a test protocol to evaluate SIPs for durability. In this chapter, details are provided on elements to assess SIP durability when subjected to conditions that simulate key parameters of the Canadian climate as may occur in-service over their expected life. In service, SIPs are exposed to physical and chemical aging. The physical processes include cyclic weathering conditions, whereas the chemical processes include oxidation and hydrolysis. The results of testing indicate that all SIP components are subject to aging deterioration under a simulated 20–50-year service life, and that aging deterioration can begin relatively early during service. Six failure modes were obtained from the tensile testing of aged SIP coupons, and these modes serve to diagnose the durability of individual SIP components. The results from this test program were used to develop guidelines to assess SIP durability.