How To Achieve R 49 In Attic

As dana mentioned use a smart vapor retarder.

How to achieve r 49 in attic. This calculator is to be used as an estimating tool only. Achieving greater r values in exterior walls in exterior walls add insulating sheathing to achieve a greater r value in your wall system. It s been a while since i dealt with insulation but i m pretty sure your gc was talking about the standard fiberglass batting the pink stuff when he said that you would need 17 inches of insulation to reach your required r value of 49. References department of energy.

Then install a sheet membrane for air tightness. The table opposite suggests r values by zone as indicated in the map of the united states. Input depth of existing blown in insulation in inches. Fill available space with roxul comfortbatts.

X 24 in 6 pieces 48 sq. 2 r 23 batts will just fit inside a 2x12 rafter for r 46. Fortunately attic insulation can be upgraded simply by adding more to achieve the recommended total depth in inches without removing existing insulation. Bag meets r 49 attic code requirements with a single batt.

For your attic project install r 49 ecotouch insulation. Click the button to calculate the approximate r value for this job. Obviously if you don t have 17 inches of attic space then you ll have to use some other kind of insulation. If you truly need r 49 that won t work but if that is just a target r 46 is close.

It also suggests r values when adding insulation to uninsulated or under insulated attics crawl spaces and walls. Spray foam insulation r values. You can achieve better thermal performance in your attic by adding an additional layer of insulation. Offers exceptional thermal and sound control performance.