I see an apparent contradiction in the code.
Minimum attic hatch size.
Tuesday january 28 2020.
Minimum vertical height of 30 inches measured from the top of the ceiling framing members to the bottom of the roof framing members.
If the opening is located in a wall the 30 inch dimension must be vertical.
Opening size requirements an attic access opening runs between the ceiling joists whenever possible.
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.
What is the minimum size for attic access opening.
1009 16 2 protection at roof hatch openings.
The clear access opening dimensions shall be a minimum of 20 inches by 30 inches 508 mm by 762 mm where such dimensions are large enough to allow removal of the largest appliance.
The rough opening cannot be less than 22 inches by 30 inches and must be located in a hallway or other readily accessible location.
The rough framed opening.
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.
20 x 30 or 22 by 30.
In buildings without an occupied roof access to the roof shall be permitted to be a roof hatch or trap door not less than 16 square feet 1 5m2 in area and having a minimum dimension of 2 feet 610 mm.
What is the minimum dimension for the attic opening.
If the access is located in the ceiling the minimum unobstructed headrom above the opening must be 30 inches measured vertically at some point over the access.
The rough framed opening must be a minimum of 22 inches by 30 inches.
Standard loft hatch sizes can only really be used with atraditional extension ladder that is placed inside the framework of the loft hatch to allow you to climb in and out of the loft.
According to the 2006 international residential code r807 1 attic access homes with combustible materials in the ceiling and roof construction must have an access to attic areas that exceeds 30 square feet and with a vertical height of 30 inches or greater.
The access opening should be located in a hallway or other readily accessible location and minimum 22 x 30.
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.
The 2007 california building code requires a minimum attic access opening of 20 inches by 30.