A.Bill Wachtler, executive director of the Structural Insulated Panel Association, responds: In general, temperatures would need to exceed 190°F before any degradation of a SIP would be possible. In a typical roof application, it’s hard to imagine that there would not be sufficient dissipation of heat to prevent temperatures from rising that high.

Nevertheless, there are preliminary reports of at least one house with a copper roof installed over SIPs that developed problems requiring investigation. That investigation is ongoing, so no conclusions can be made yet. In the meantime, I recommend checking with the copper roofing manufacturer and supplier, as well as the SIP manufacturer, concerning proper application procedures. Until better data are available, I would recommend a cool roof application for copper. A cool roof application creates an air space between the SIP roof panels and the metal roofing.