Minimum Attic Opening Size

Minimum opening size the 2012 international residential code requires an attic access opening for attics with an area greater than 30 square feet and a vertical height in excess of 30 inches.

Minimum attic opening size.

When the access is located in a ceiling minimum unobstructed headroom in the attic space shall be 30 inches 762 mm at some point above the access measured vertically from the bottom of ceiling framing members. If the access is located in the ceiling the minimum. The rough opening cannot be less than 22 inches by 30 inches and must be located in a hallway or other readily accessible location. Minimum vertical height of 30 inches measured from the top of the ceiling framing members to the bottom of the roof framing members.

The rough framed opening must be a minimum of 22 inches by 30 inches. Note about attic clearance. When located in a wall the opening shall be a minimum of 22 inches wide by 30 inches high 559 mm wide by 762 mm high. Deep minimum the full width of opening must be present in attic.

For smaller attic openings with a minimum measurement of 18 x 24 you will need to measure the swing clearance inside the attic space. If the attic space is smaller than these specs then an access hatch is not required. This 20 limitation applies to the minimum 30 height only low clearance attics. Minimum clearance required above attic opening.

If the opening is located in a wall the 30 inch dimension must be vertical. Unobstructed headroom of at least 30 inches must be available above the attic opening. The 2007 california building code requires a minimum attic access opening of 20 inches by 30. The other is minimum for attics containing appliances and this latter one is more restrictive as it also includes where such dimensions are large enough to allow removal of the largest appliance meaning that the opening may actually be required to be.

What is the minimum size for attic access opening. To mount assist arm on attic floor 3 4 in. Minimum clearance required behind opening. Tuesday january 28 2020.

One is a minimum for any attic which has the required 30 headroom vertical height. The compact attic ladder requires a minimum height of 28 and minimum depth of 44 inside the attic above and behind the opening. If there are no obstructions on the passageway to the attic furnace and it has a minimum 6 feet 1829 mm height and 22 inches 559 mm width along its entire run the walkway length limit goes up to 50 feet 15250 mm in irc international residential code and has no limit in umc universal mechanical code.