Michigan Basement Egress Window Requirements

Exterior view of an egress window in a basement bedroom. These windows are required as part of the USA fire code for basement bedrooms
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Egress window requirements may sound like a picky, administrative topic, but anyone stuck in a burning building will appreciate the underlying importance of these laws. The term simply refers to windows that a person can use as an emergency exit in a home.

Windows or doors that offer a safe emergency exit are a critical concept in every bedroom. They provide an escape route if someone wakes up and finds the house on fire. Michigan mandates some type of emergency escape and rescue opening in most sleeping areas; in basements, these are usually windows.

Michigan Building Code

Egress window requirements in Michigan are taken from the model code, International Residential Code. Many states have adopted this model, including Michigan.

The International Residential Code (IRC) is a model code that provides standards used worldwide to construct safe, sustainable, affordable and resilient structures. It comprises building, plumbing, mechanical, fuel gas and electrical standards for one- and two-family homes and townhouses up to three stories.

It also includes emergency escape and rescue openings in Section R310 and egress window requirements in Section R311

Emergency Escape and Rescue Openings

In IRC R310, the code sets out regulations about emergency escape and rescue openings. These are doors or windows that open onto a public way, or a yard or court that opens into a public way.

Every room where someone will sleep must have an escape and rescue opening, including habitable attics and basement sleeping areas. Windows that meet the requirements can be used as emergency escape and rescue openings.

Doors and windows that are considered emergency escape and rescue openings must be operational from the inside of the sleeping area without a key. Opening them cannot require tools or special knowledge, either. If the escape opening is a window, any bars on the window must also be removable from the inside without tools. This makes sense since the intention is to allow anyone trapped inside to get out in an emergency.

Michigan Egress Codes

Michigan enacted its own Residential Code using the 2015 IRC as a base. The state hasn't updated the code since 2015. Michigan’s Residential Code, beginning with section R310 sets out the basic egress laws for state residential housing. It is based on the IRC code section of the same number.

Although certain parts of the model code were amended by the Michigan state legislature, nothing regarding emergency escape and rescue openings seems to have been altered.

Requirements for Emergency Escape Window Openings

The section of Michigan law repeats the IRC rule that requires that basements, habitable attics and every sleeping room in a house or townhouse has at least one operable emergency escape and rescue opening.

Like the IRC requirements, Michigan law mandates that emergency escape and rescue openings open directly into a public way, or to a yard or court that opens to a public way.

Windows as Emergency Escape Openings

Note that the code requires an emergency escape and rescue opening in every room used for sleeping, in habitable attics and in basements with sleeping rooms. It does not require that a window be used as an emergency escape opening in these rooms.

If a room has another opening, like a door, that leads directly outside and meets the requirements set out in the code, it is not necessary that the windows also meet the egress requirements.

Basements, however, will not have exterior wall doors. By definition, basements are built partially below ground level. That is why window egress requirements are particularly important.

Michigan Egress Window Code Requirements

What are the egress window requirements in Michigan? As is the case for all emergency escape openings, a window used as an escape opening must be capable of being opened from the inside without the use of keys, tools or special knowledge. The height of the window sill is also regulated – it cannot be more than 44 inches above the floor.

The window must have an unobstructed opening with a minimum area of 5.7 square feet. It can be configured in several ways, but the opening must have a height of 24 inches or more, with a width of 20 inches or more. Note that if the window is a double-hung window or a horizontal slider window, only the part that opens is included in the total opening calculation.

Basement Window Well Minimum Dimensions

With grade floor or below grade openings, the minimum area of unobstructed opening is reduced to 5 square feet. And if the sill height is below grade, a window in Michigan must have a window well. That window well must fit within particular specifications:

  • It must be at least 9 square feet in an area with a horizontal projection, and a width of at least 36 inches.
  • If the well is deeper than 44 inches, it must have permanent steps or a ladder.
  • These features, when in use, cannot impair the full opening of the egress window.
  • If a ladder is required, there are specifications for the rungs as well. They must be spaced at 18 inches or less, and must have an insider width of at least 12 inches and project 3 inches from the wall.

Escape Opening Exceptions in Michigan

Most laws have exceptions, and Michigan's emergency escape opening laws have exceptions as well. These are a few good ones to know:

  • If a habitable space is in a basement or below the fourth floor of a building, it is not required to have emergency escape or rescue openings, including egress windows, if the area is equipped with an approved automatic sprinkler system that acts as a safety device in the event of a fire.
  • If a habitable space in a dwelling has an exit door that opens directly to a public area, this can serve as an alternate escape route. In this case, the windows need not comply with the egress window restrictions.