Mississippi Avenue Lofts, a mixed use residential and commercial building, was experiencing problems with its roof system. The building used Structural Insulated Panels, commonly known as SIPs, and was experiencing sheathing damage along the SIP panel seams. Pacific Building Insight was asked to evaluate the cause of the moisture intrusion and find a solution to the issue.

SIPs panels consist of orientated strand board (OSB) sheathing adhered to both sides of an insulated foam core. These panels were designed to replace standard framing and insulation systems.

The roof membrane appeared to be intact and functioning properly, however, we still needed to find a solution to the cause of the sheathing damage. After dew point analysis was performed, it was determined that the dew point was between the roofing and the tops of the SIPs panels.

Our proposed solution was to over frame an air cavity between the top of the SIPs panels and the bottom of the roof to allow for air circulation to move the dew point above the roof membrane.