Michigan Basement Egress Window Requirements

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A home's square footage can be expanded by finishing and making use of the basement which creates additional living space. For safety, all habitable spaces, especially sleeping areas should be equipped with escape routes in the event of a fire. The state of Michigan requires the use of egress windows in all most all cases.


Michigan’s residential Code, section R310.1 states that egress windows are required in all habitable spaces and sleeping areas in a basement that is below the fourth floor of the building. This requirement applies to all buildings regardless if they are newly contrasted or older homes that have been remodeled.


Habitable space is defined in section R201.1 and R202 of the International Building Code as space in a building for living, sleeping, eating or cooking. Any areas, such as bathrooms, storage closets and utility spaces are therefore not considered habitable spaces. Areas in a basement with habitable spaces only are required to implement egress windows or rescue openings.

Window Requirements

The sill of an egress window must be within 44 inches of a finished floor, a minimum of 20 inches in width providing a clear opening and 24 inches in height providing a clear opening. Combined opening area must be a minimum of 5.7 square feet. Egress windows must be easily opened without special skills, effort or tools and security bars and grills are prohibited except under certain situations.

Window Well Requirements

Minimum window well requirements include 9 square feet of horizontal area and 36 inches of minimum width and should allow for the egress window to open fully. Window wells with a vertical depth (ground to ground) greater than 44 inches are required to be equipped with a permanently affixed ladder or steps that are operational when the egress window is fully open. In the event of a required ladder, rungs must have an insider width of at least 12 inches and project 3 inches from the wall. Spacing between rungs shall not exceed more than 18 inches.


Habitable spaces in a basement or below the fourth floor of the building are not required to be equipped with egress windows or emergency escape when the area is equipped with an approved automatic sprinkler system that acts as a safety device in the event of a fire. An additional exception is granted when habitable spaces are designed with an exit door that opens directly to a public area, allowing for an alternate escape route.