Rating System

LEED BD+C: New Construction

Rating System Version

v2 - LEED 2.1

Inquiry

Icynene Roof Insulation The roof construction for this project in Palmer, Alaska consist of standing seam metal over 1-inch thermal blocks over steel roof purlins spanning between structrual steel frames. The traditional insulation system for this type of construction is a fiberglass batt insulation with a vinyl facing draped over the roof purlins prior to installing the standing seam metal roof system. In a metal building in the artic environment, the temperature of the the air in the roof cavity can fluctuate gratly due to cool day time temperatures, solar warming of the roof panels, and cold night time temperatures. As the temperature of the miniature weather system, inside the roof cavity, rises and falls so does the dew point. As this temperature and dew point graph continue to cross, moisture is released in the form of condensation. Especially vulnerable are the areas of the roof with open-air void spaces. Void spaces greatly multi[ply the effect of this cycle to accumulate moisture, thus multiplying the ability of accumulated moisture to damage interior finishes and decrease the insulating value of the insulation over the life span of the facility. The roof insulation used for this project is a polyicynene insulation maunfactured by Icynene Inc. A 7/8-inch hat channel was placed perpendicular to the roof purlins and the entire roof cavity was sprayed completely full with the Icynene insulation, providing an R-value of 41. The underside of the icynene was then covered with a vapor barrier and 5/8-inch gypsum wallboard. Icynene fills the cavity, adhereing to the structure and creating an insulation blanket that has minimal air permeance and seals the building against air leakage. Convective air movement inside the roof cavity is virtually eliminated, thus reducing the likely hood of condensation from forming in the roof cavity. Icynene contains no formaldehyde, CFC\'\'s or HCFC\'\'s.