How To Achieve R 49 In Attic

Amongst all of the popular types of insulation currently used by the industy spray foam insulation features the highest r value per inch.

How to achieve r 49 in attic.

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. If you truly need r 49 that won t work but if that is just a target r 46 is close. 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. Input depth of existing blown in insulation in inches.

Achieving greater r values in exterior walls in exterior walls add insulating sheathing to achieve a greater r value in your wall system. Spray foam insulation r values. References department of energy. Click the button to calculate the approximate r value for this job.

X 24 in 6 pieces 48 sq. Evaluate your house s current r value and recommend whether additional r value is needed and appropriate types of insulation. Fill available space with roxul comfortbatts. 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. Fortunately attic insulation can be upgraded simply by adding more to achieve the recommended total depth in inches without removing existing insulation. As dana mentioned use a smart vapor retarder. Offers exceptional thermal and sound control performance.

Bag meets r 49 attic code requirements with a single batt. Obviously if you don t have 17 inches of attic space then you ll have to use some other kind of insulation. It also suggests r values when adding insulation to uninsulated or under insulated attics crawl spaces and walls. You can achieve better thermal performance in your attic by adding an additional layer of insulation.