R30 Roof Rafters

R30c and r38c are available in both kraft faced and unfaced.

R30 roof rafters.

Better than spray foam thermal break and relatively consistent r 30. By installing high density 8 inch fiberglass batt insulation the rafters will then meet an r 30 roof insulation standard. If you re using fiberglass insulation you need thicker wall or ceiling cavities to fit insulation with a higher r value. And owens corning ecotouch high density insulation products are designed specifically for these rafters.

Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run. I 39 m stapling the bats between two 2x8 rafters and the attic roof. The rafters in cathedral ceilings are usually made of 2 in. The fresh air flows up between rafters to the ridge where a ridge vent roof vents or gable vents allow the air to exit.

39 installing r30 bat insulation 2x8 rafters compress insulation fit. If you re framing a gable roof on a new house or building a shed or even a doghouse with a gable roof you ll need to cut a number of roof rafters. R30 needs 9 inches. If insulation is allowed to bunch against the inside slope of the roof between the rafters air will be blocked before it can traverse the attic.

Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter. Owens corning r 30 ecotouch pink cathedral ceiling kraft faced fiberglass insulation batt 23 3 4 in. Raft r mate attic rafter vents create a space between each rafter for air to. The roof rafters provide integral structural support to the roof.