Tech Today

Roofing research findings

In March, RCI Inc. held its 29th International Convention and Trade Show. The event included 21 educational sessions offered in a symposium-style format with formal presentations and papers published in proceedings. Following is a brief overview of several of the roofing-related topics.

Measuring thermal benefits

In "Conventional Roofing Assemblies: Measuring the Thermal Benefits of Light to Dark Roof Membranes and Alternative Insulation Strategies," Graham Finch, building science engineer with RDH Building Engineering Ltd., Vancouver, British Columbia, presented the results of a field and laboratory research project of a test roof consisting of three (white, gray and black) two-ply SBS polymer-modified bitumen membranes installed over three insulation types (polyisocyanurate, mineral wool, and a hybrid of a polyisocyanurate base layer and a mineral wool cover board). The three insulation types were installed to have a similar overall R-value.

The research findings show the roof systems with a mineral wool insulation and hybrid insulation combination maintain R-values close to their published R-values, whereas the polyisocyanurate insulation roof system's R-value notably dropped when exposed to cold or hot outdoor temperatures and solar radiation-induced temperatures.