Products / Defend-R Vent

Defend-R Vent is a vented nail base insulation panel for steep-slope roofs: a 4 by 8 foot closed-cell polyisocyanurate board, solid wood spacers forming a standard 1-inch air space (1.5 and 2 inch spacers also offered), and a top layer of 7/16 or 5/8 inch OSB or 5/8 or 3/4 inch CDX or fire-treated plywood. Overall thicknesses run 2.5 to 5 inches, and it is for slopes of 3:12 or greater under standing seam metal, shingles, natural and synthetic slate, and tile, including cathedral ceilings, exposed decks, log homes and post-and-beam work. The TDS lists ASTM C1289 Type II Class 1 Grade 2 foam and states the air space exceeds ARMA Tech Bulletin 211-RR-24 minimum depth.