Noah Kalina

Designed for use on shingle and metal roofs, Cornell Corp.’s Vent-Top ThermaCal 1 system consists of 7/16" OSB sheathing, 1" wood spacer blocks, and polyisocyanurate insulation board offered in thicknesses between 3" and 8". The fully machined assembly offers R-values between 9 and 40.5 and weighs between 1.9 to 2.9 psf. The edges of the 4'-by-8' panels feature rabbeted wood and a tongue-and-groove pattern in the foam to reduce heat loss. The 12"-o.c. wood spacers allow for 86% up-slope venting and more than 50% cross ventilation. •