Basement Bedroom Window Requirements

 Moved from evernote. Last edited 12/14/23

http://www.inman.com/2007/12/04/when-does-basement-qualify-legal-bedroom/

The openable portion of a bedroom window must have a minimum dimension of 5.7 square feet, unless the sill is lower than the outside grade level. In that case, the overall dimension must be at least 9 square feet. The width of window openings must be no less than 24 inches and the height no less than 20 inches. If the windowsill in a basement bedroom is lower than the outside grade level, there must be an exterior window well that meets an additional list of minimum size requirements.

Windowsills in any bedroom must be no higher than 44 inches above the floor, although lower sills were often allowed in older homes. In a basement bedroom, sill heights can exceed 44 inches if there is a permanently installed ladder or stairway to the window opening.

As a source for natural light, the area of the window, according to the Uniform Building Code (UBC), must be no less than one-tenth of the room’s floor area. In municipalities subject to the International Residential Code (IRC), this requirement is only 8 percent of the floor area.

As a source of exterior ventilation, the UBC requires the area of the window opening to be no less than one-twentieth of the room’s floor area. According to the IRC, only 4 percent of the floor area is required.