How To Achieve R 49 In Attic

Evaluate your house s current r value and recommend whether additional r value is needed and appropriate types of insulation.

How to achieve r 49 in attic.

Bag meets r 49 attic code requirements with a single batt. Then install a sheet membrane for air tightness. X 24 in 6 pieces 48 sq. The table opposite suggests r values by zone as indicated in the map of the united states.

Achieving greater r values in exterior walls in exterior walls add insulating sheathing to achieve a greater r value in your wall system. Obviously if you don t have 17 inches of attic space then you ll have to use some other kind of insulation. You can achieve better thermal performance in your attic by adding an additional layer of insulation. Input depth of existing blown in insulation in inches.

Click the button to calculate the approximate r value for this job. For example energy star recommends r 30 for a roof in the southern united states r 38 for the middle of the country and r 49 for the northern part of the country. It also suggests r values when adding insulation to uninsulated or under insulated attics crawl spaces and walls. This calculator is to be used as an estimating tool only.

Fill available space with roxul comfortbatts. If you truly need r 49 that won t work but if that is just a target r 46 is close. As dana mentioned use a smart vapor retarder. Offers exceptional thermal and sound control performance.

For your attic project install r 49 ecotouch insulation. Spray foam insulation r values. 2 r 23 batts will just fit inside a 2x12 rafter for r 46. References department of energy.