R30 Roof Rafters

And owens corning ecotouch high density insulation products are designed specifically for these rafters.

R30 roof rafters.

Better than spray foam thermal break and relatively consistent r 30. I 39 m stapling the bats between two 2x8 rafters and the attic roof. For instance if the roof has 2 by 6 rafters and you want r 30 insulation which is standard in many communities you can add a 2 by 4 which will give you an 9 inch rafter space. The rafters in cathedral ceilings are usually made of 2 in.

Owens corning r 30 ecotouch pink cathedral ceiling kraft faced fiberglass insulation batt 23 3 4 in. By installing high density 8 inch fiberglass batt insulation the rafters will then meet an r 30 roof insulation standard. R30c and r38c are available in both kraft faced and unfaced. Raft r mate attic rafter vents create a space between each rafter for air to.

Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch. 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. If you re using fiberglass insulation you need thicker wall or ceiling cavities to fit insulation with a higher r value. Before you cut your boards you ll need to measure the width of your building and calculate the exact length of each rafter.

The fresh air flows up between rafters to the ridge where a ridge vent roof vents or gable vents allow the air to exit. 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. Here s how to use 3 layers of 2 inch polyiso foam board to meet code and keep your ne. R30 needs 9 inches.