Failure Analysis of Spray Polyurethane Foam (SPF) Insulation

Spray polyurethane foam (SPF) is a widely used plastic foam commercial material. When installed as a structural insulator in commercial and residential construction properties, it has several advantages over competing materials like fiberglass and cellulose, including more effective insulative properties (higher R value), improved air and moisture barrier capability, and enhanced structural integrity. A drawback is that it is manufactured in place, and in residential applications this means the SPF manufacturing facility is the attic and wall cavities of structures that will soon be inhabited. If applied and installed appropriately, the SPF cures within 24-48 hours and functions as intended for decades. However, there are various parameters during manufacturing and installation that can impact the ability of the foam to function properly as an insulator and also affect the amount of off-gassing that occurs. Additionally, failures in other building materials can also be caused by SPF due to ingredients present in the formulation or the foam’s ability to seal a structure more air-tight than what was considered when the HVAC system was designed.

In this presentation, the chemistry of SPF insulation will be summarized, and potential defects discussed along with methods to identify these defects as part of case studies from failure analysis projects involving SPF. Typically, a combination of visual observation and analytical testing is used to identify issues in the SPF.