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.
Required attic access 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.
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.
Access opening and an unobstructed passage way to the appliance furnace in attic area must be provided and be adequate in size to allow removal of the largest appliance installed.
The minimum size for an attic s access building codes.
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.
The vertical height shall be measured from the top of the ceiling framing members to the underside of the roof framing members.
Buildings with combustible ceiling or roof construction shall have an attic access opening to atticareas that exceed 30 square feet 2 8 m2 and that have a vertical height of 30 inches 762 mm or greater over an area of not less than 30 square feet.
20 inches 508 mm by 30 inches 762 mm minimum.
The compact attic ladder requires a minimum height of 28 and minimum depth of 44 inside the attic above and behind the opening.
These specs are per r807 1 of the international residential code irc and the residential edition of the florida building code fbc.
The rough framed opening.
For smaller attic openings with a minimum measurement of 18 x 24 you will need to measure the swing clearance inside the attic space.
According to the 2006 international residential code r807 1 attic access homes with combustible.
The attic may be accessed through a scuttle door or attic hatch usually located in a closet or main hallway.
Attic furnace appliance clear access opening dimensions are.
Attic area exceeds 30 square feet and minimum vertical height of 30 inches measured from the top of the ceiling framing members to the bottom of the roof.