Minimum of 22 inches wide by 30 inches high 559 mm wide by 762 mm high.
Min size of attic access panel in cbc.
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.
The rough framed opening must be a minimum of 22 inches by 30 inches.
Openings through a perimeter wall shall be not less than 16 inches by 24 inches 407 mm by 610 mm.
According to california mechanical code section 303 9 roof access panels must have a clearance of at least 30 inches allowing personnel to safely access any rooftop equipment or enclosure.
See the california mechanical code for access requirements where mechanical equipment is located in attics.
When any portion of the through wall access is below grade an areaway not less than 16 inches by 24 inches 407 mm by 610 mm shall be provided.
Building codes 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.
Crc r502 9 crc r602 3 and crc r802 2 2.
Here s the full text of the code.
A minimum 30 inches 762 mm by 30 inches 762 mm level service platform space is required in front of the attic furnace s attic appliance service access panel.
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.
The rough framed opening.
The number size and spacing of fasteners connecting wood members elements shall not be less than that set forth in crc tabl e r602 3 1.
Buildings with combustible ceiling or roof construction shall have an attic access opening to attic areas that have a vertical height of 30 inches 762 mm or greater over an area of not less than 30 square feet 2 8 m 2.
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.
The size height and spacing.
The vertical height shall be measured from the top of the ceiling framing members to the underside of the roof framing members.