Legal Egress Window Size In Minnesota

The height of the clear opening of an

Emergency escape/ Egress window 

must be at least 24"H and width must be at least 20"W.

• The Egress window must provide an unobstructed opening with a minimum area of 5.7 sq. ft. 

• The Egress window sill height must not be more than 44" above the floor.

• The Egress window must be openable from the inside without the use of keys or tools.

• If the Egress window sill height is below grade, the Egress window must have a window well.

• The Egress window well must be at least 9 sq. ft. in area with a horizontal projection and a width of at least 36" each way.

• Egress Window wells deeper than 44" must have permanent steps or a ladder that do not impede the opening of the Egress windows.

• If there is more than one sleeping room in a basement, a means of egress is required in each sleeping room.                            

                   

  Section R310:

  Emergency Escape Windows and Rescue Openings.

   

  R310.1 Emergency escape windows and rescue opening required.

  Basements, habitable attics and every sleeping room shall have not less than one operable emergency escape window and rescue opening. Where basements contain one or more sleeping rooms, an emergency escape and rescue opening shall be required in each sleeping room.

  Emergency escape windows and rescue openings shall open directly into a public way, or to a yard or court that opens to a public way. 

  
   

  R310.1.1 Operational constraints and opening control devices. 

  Emergency escape windows and rescue openings shall be operational from

  the inside of the room without the use of keys, tools or special knowledge.

  Window opening control devices complying with ASTM F 2090 shall be permitted

  for use on windows serving as a required emergency escape windows

  and rescue opening.

   

  R310.2 Emergency Escape And Rescue Openings.

  Emergency escape and rescue openings shall have minimum dimensions as specified in this section.

   

  R310.2.1 Minimum Opening Area.

  Emergency windows and escape rescue openings shall have a net clear opening of not less than 5.7 sq. ft.

  The net clear opening dimensions required by this section shall be obtained by the normal operation of the

  emergency escape and rescue opening from the inside.

  The net clear height opening shall be not less than 24" and the net clear width shall be not less than 20". 

   

  R310.2.2 Egress Window Sill Height.

  Where a window is provided as the emergency escape window and rescue opening, it shall have a sill height of not more than 44" above the floor; where the sill height is below grade, it shall be provided with a window well in accordance with Section R310.2.3.

   

  R310.2.3 Egress Window Wells.

  The horizontal area of the egress window well shall be not less than 9 sq. ft, with a horizontal projection and width of not less than 36". The area of the egress window well shall allow the emergency escape window and rescue opening to be fully opened.

   

  Exception: The Egress ladder or steps required by Section R310.2.3.1 shall be permitted to encroach not more than 6" into the required dimensions of the egress window well.

   

  R310.2.3.1 Egress Ladder and steps.

  Egress Window wells with a vertical depth greater than 44" shall be equipped with a permanently affixed ladder or steps usable with the window in the fully open position.Egress ladders or steps required by this section shall not be required to comply with Sections R311.7 and R311.8.Egress ladders or rungs shall have an inside width of not less than 12", shall project not less than 3" from the wall and shall be spaced not more than 18" on center vertically for the full height of the egress window well. 

   

  R310.2.3.2 Egress Window Well Drainage.

  Window wells shall be designed for proper drainage by connecting to the building’s foundation drainage system required by Section R405.1 or by an approved alternative method.

   

  Exception: A drainage system for a egress window wells is not required where the foundation is on well-drained soil or sand-gravel mixture soils in accordance with the United Soil Classification System, Group I Soils, as detailed in Table R405.1.

   

  R310.2.4 Emergency Escape Windows And Rescue

  Openings Under Decks And Porches.

  Emergency escape windows and rescue openings shall be permitted to be installed under decks and porches provided that the location of the deck allows the emergency escape and rescue openings to be fully opened and provides a path not less than 36" in height to a yard or court.

   

  R310.4 Bars, Grilles, Covers And Screens.

  Bars, grilles, covers, screens or similar devices are permitted to be placed over emergency escape windows and egress openings, bulkhead enclosures, or window wells that serve such openings, provided that the minimum net clear opening size complies with Sections R310.1.1 to R310.2.3, and such devices shall be releasable or removable from the inside without the use of a key, tool, special knowledge or force greater than that required for the normal operation of the escape and rescue opening.

A window must meet certain requirements to pass the state of Wisconsin's egress window code. This building code ensures inhabitants have a second means of exit from a basement living space, in the event of an emergency. 

Section​ 1030: Emergency Escape and Rescue Windows.

1030.1 General.

In addition to the means of egress required by this chapter, provisions shall be made for emergency escape and rescue openings in Group R-2 occupancies in accordance with Tables 1006.3.2(1) and 1006.3.2(2) and Group R-3 occupancies. Basements and sleeping rooms below the fourth story above grade plane shall have at least one exterior emergency escape and rescue opening in accordance with this section. Where basements contain one or more sleeping rooms, emergency escape and rescue openings shall be required in each sleeping room, but shall not be required in adjoining areas of the basement. Such openings shall open directly into a public way or to a yard or court that opens to a public way.

Exceptions: 

1. Basements with a ceiling height of less than 80" shall not be required to have emergency escape and rescue openings.

2. Emergency escape and rescue openings are not required from basements or sleeping rooms that have an exit door or exit access door that opens directly into a public way or to a yard, court or exterior exit balcony that opens to a public way.

3. Basements without habitable spaces and having not more than 200 sq. ft. in floor area shall not be required to have emergency escape and rescue openings. 

1030.2 Minimum Size.

Emergency escape and rescue openings shall have a minimum net clear opening of 5.7 sq. ft.

Exception: The minimum net clear opening for grade-floor emergency escape and rescue openings shall be 5 sq. ft.

1030.2.1 Minimum Dimensions.

The minimum net clear opening height dimension shall be 24". The minimum net clear opening width dimension shall be 20". The net clear opening dimensions shall be the result of normal operation of the opening.

1030.3 Maximum Height From Floor.

Emergency escape and rescue openings shall have the bottom of the clear opening not greater than 44" measured from the floor.

1030.4 Operational Constraints.

Emergency escape and rescue openings shall be operational from the inside of the room without the use of keys or tools. Bars, grilles, grates or similar devices are permitted to be placed over emergency escape and rescue openings provided the minimum net clear opening size complies with Section 1030.2 and such devices shall be releasable or removable from the inside without the use of a key, tool or force greater than that which is required for normal operation of the emergency escape and rescue opening. Where such bars, grilles, grates or similar devices are installed in existing buildings, smoke alarms shall be installed in accordance with Section 907.2.11 regardless of the valuation of the alteration.

1030.5 Window Wells.

An emergency escape and rescue opening with a finished sill height below the adjacent ground level shall be provided with a window well in accordance with Sections 1030.5.1 and 1030.5.2. 

1030.5.1 Minimum Size.

The minimum horizontal area of the window well shall be 9 sq. ft., with a minimum dimension of 36". The area of the window well shall allow the emergency escape and rescue opening to be fully opened.

1030.5.2 Ladders or Steps.

Window wells with a vertical depth of more than 44" shall be equipped with an approved permanently affixed ladder or steps. Ladders or rungs shall have an inside width of at least 12", shall project at least 3" from the wall and shall be spaced not more than 18" on center (o.c.) vertically for the full height of the window well. The ladder or steps shall not encroach into the required dimensions of the window well by more than 6". The ladder or steps shall not be obstructed by the emergency escape and rescue opening. Ladders or steps required by this section are exempt from the stairway requirements of Section 1011.  

      Wisconsin Administrative Code

In addition to specific egress window requirements, the state of Wisconsin also has natural light requirements that you must abide by. These natural light requirements are detailed by the Wisconsin Administrative Code, specifically Chapter SPS 321. Please contact your local county building inspector to confirm your code requirements.

SPS 321.05 Natural light and natural ventilation.

1. Natural Light.

Each habitable room shall be provided with natural light by means of glazed openings. The area of the glazed openings shall be at least 8% of the net floor area, except under the following circumstances:

(a) Exception: Habitable rooms, other than bedrooms, located in basements, ground floors or above garages do not require natural light.

(b) Exception: Natural light may be obtained from adjoining areas through glazed openings, louvers or other approved methods. Door openings into adjoining areas may not be used to satisfy this requirement. 

1. Dwellings consisting of no more than a first floor with a maximum floor area of 400 square feet and a loft area not exceeding half of the first floor area, shall be provided with at least one exit door leading directly to the exterior and at least one egress window that complies with sub. (6).

2. a. Dwellings that meet the size restrictions under subd. 1., are not required to meet the exit separation requirements under par. (e) or (f).

b. If a dwelling that meets the size restrictions under subd. 1., has more than one room on the first floor, the door and the egress window shall be located in different rooms.

3. One of the exit doors required in par. (a) may be omitted for a dwelling unit that has one or more egress windows on the first floor. If there are bedrooms, each must have a window that complies with sub. (6).

(2)  Exits from the second floor.

(a) At least 2 exits shall be provided from the second floor. At least one of the exits shall be a stairway or ramp and lead to the first floor or discharge to grade. The second exit may be via a stairway or ramp that discharges to grade, or to a balcony which complies with sub. (8), or to a deck that complies with s. SPS 321.225 and that is no more than 15 feet above the grade below.

(b) Windows that comply with sub. (6) may be provided in each second floor bedroom — or in another location on the second floor if there are no bedrooms on that floor — in lieu of the second exit from that floor.

(c) Where the second floor of a building is the lowest floor level in a dwelling unit, as in an up-and-down duplex, no exit from the unit may go through another dwelling unit or other party's occupancy on the first floor.

(3)  Exits above the second floor.

(a) Except as provided under pars. (b) and (c), each habitable floor above the second floor shall be provided with at least 2 exits that meet all of the following requirements:

1. The exits shall be stairways or ramps that lead to the second floor or discharge to grade.

2. The exits shall be located such that an exit is accessible to the second floor if another exit is blocked.

(b) A second stairway or ramp exit is not required for habitable areas on a third floor that meet all of the following requirements:

1. The habitable area consists of a single room.

Note: Non-habitable areas, such as closets and bathrooms may be partitioned off.

2. The room is not used for sleeping.

3. The habitable area has a floor area of 400 square feet or less.

4. There is at least one egress window meeting the requirements of sub. (6) in the habitable area.

(c) A second stairway or ramp exit is not required for habitable areas on a third floor that meet all of the following requirements:

1. The dwelling is fully sprinklered in accordance with NFPA 13R or NFPA 13D.

2. If a required exit includes an attached garage, the garage shall be sprinklered.

(4)  Exits from lofts.

(a) At least one stairway exit shall be provided, to the floor below, for a loft exceeding 400 square feet in area.

(b) At least one stairway or ladder exit shall be provided to the floor below for a loft, 400 square feet or less, in area.

(5)  Exits from basements and ground floors.

(a) General. Except as provided in par. (b), all basements and ground floors shall be provided with at least one exit of the following types:

1. A door to the exterior of the dwelling.

2. A stairway or ramp that leads to the floor above.

(b) Basements and ground floors used for sleeping.

1. Basements and ground floors used for sleeping shall be provided with at least 2 exits.

2. The exits shall be located as far apart as practical.

3. The exits may not be accessed from the same ramp or stairway.

4. In addition to the exit type required under par. (a), the second exit from a basement or ground floor used for sleeping shall be one of the following types:

a. A door to the exterior of the dwelling.

b. A stairway or ramp that leads to the floor above.

c. A stairway that leads to a garage provided the garage has an exit door other than the overhead door.

d. An egress window that complies with sub. (6), located in each bedroom.

(6)  Windows used for exiting. Windows which are installed for exit purposes shall comply with the requirements of this subsection.

(a) The window shall be openable from the inside without the use of tools or the removal of a sash. If equipped with a storm or screen, it shall be openable from the inside.

(b) 1. The nominal size of the net clear window opening shall be at least 20 inches by 24 inches irrespective of height or width. Nominal dimensions shall be determined by rounding up fractions of inches if they are ½-inch or greater or rounding down fractions of inches if they are less than ½-inch.

 2. No portion of the window, including stops, stools, meeting rails and operator arms, shall infringe on the required opening.

(c)  The area and dimension requirements of par. (b) may be infringed on by a storm window.

(d) 1. For any window used for exiting, the lowest point of clear opening shall be no more than 60 inches above the floor.

2. If the lowest point of clear opening is more than 46 inches above the floor, a permanent platform or fixture shall be installed such that a flat surface at least 20 inches wide and 9 inches deep is located no more than 46 inches directly below the clear opening.

3. The topmost surface of the platform or fixture shall be no more than 24 inches above the floor.

4. The topmost surface of the platform or fixture shall support a live load of at least 200 pounds.

5. A stair used for the sole purpose of reaching the top of the platform or fixture is exempt from the requirements of s. SPS 321.04.

(e)

1. An egress window with any point of clear opening below adjacent grade shall be provided with an areaway in accordance with this section.

2. The width of the areaway shall be at least equal to the width of the window.

3. The areaway shall be a minimum of 36 inches measured perpendicular from the outer surface of the below-grade wall.

4. If the bottom of the areaway is more than 46 inches below adjacent grade or the top of the areaway enclosure, the areaway shall be provided with a ladder or stair to aid egress. Stairs used to comply with this section are exempt from the requirements of s. SPS 321.04.

5. a. Ladders or other stairs used to comply with subd. 4. may infringe on the required area of the areaway by a maximum of 6 inches.

b. Ladder rungs shall have a minimum inside width of at least 12 inches and shall project at least 3 inches from the wall behind the ladder.

c. Ladder rungs shall be able to support a concentrated load of 200 pounds.

d. Ladder rungs shall have a maximum rise of 12 inches between rungs and shall extend to within 12 inches of exterior grade.

6. The areaway shall be constructed such that water entering the areaway does not enter the dwelling.

(f) An egress window under a deck or porch shall discharge through a clear path of at least 36 inches in height and 36 inches in width, and no more than 15 feet in length, to a yard or open space.

Note: Under this paragraph, there is no maximum height above grade for an egress window. Similarly, egress windows are not prohibited from discharging to a roof, regardless of the slope of the roof.

The minimum opening area of the egress window is 5.7 square feet. The minimum egress window opening height is 24" high. The minimum egress window opening is 20" wide. * Multiple windows can be used to service a single area where one window does not meet these percentages of total floor area.

R310.1 Emergency escape and rescue required.

Basements, habitable attics, and every sleeping room shall have at least one operable emergency escape and rescue opening. Where basements contain one or more sleeping rooms, emergency egress and rescue openings shall be required in each sleeping room, but not be required in adjoining areas of the basement. Where emergency escape and rescue openings are provided they shall have a sill height of not more than 44 inches (1118 mm) measured from the finished floor to the bottom of the clear opening. Where a door opening having a threshold below the adjacent ground elevation serves as an emergency escape and rescue opening and is provided with a bulkhead enclosure, the bulkhead enclosure shall comply with Section R310.3. The net clear opening dimensions required by this section shall be obtained by the normal operation of the emergency escape and rescue opening from the inside. Emergency escape and rescue openings with a finished sill height below the adjacent ground elevation shall be provided with a window well in accordance with Section R310.2. Emergency escape and rescue openings shall open directly into a public way, or to a yard or court that opens to a public way.

Exceptions:
A.Constructed prior to August 1, 2008;
B.Undergoing an alteration or repair; and
C.The entire basement area, when all portions of the means of egress to the level of exit discharge, and all areas on the level of exit discharge that are open to the means of egress is protected with an automatic sprinkler system in accordance with IRC Section P2904 or NFPA 13D.
1.Basements used only to house mechanical equipment and not exceeding total floor area of 200 square feet (18.58 m2).
2.Basements or basement bedrooms when the building is protected with an automatic sprinkler system installed in accordance with IRC Section P2904 or NFPA 13D.
3.Basements or basement bedrooms that comply with all of the following conditions:

R310.1.1 Minimum opening area.

All emergency escape and rescue openings shall have a minimum net clear opening of 5.7 square feet (0.530 m2).

Exception: Grade floor openings shall have a minimum net clear opening of 5 square feet (0.465 m2).

R310.1.2 Minimum opening height.

The minimum net clear opening height shall be 24 inches (610 mm).

R310.1.3 Minimum opening width.

The minimum net clear opening width shall be 20 inches (508 mm).

R310.1.4 Operational constraints.

Emergency escape and rescue openings shall be operational from the inside of the room without the use of keys, tools, or special knowledge.

Exception: Windows with approved window opening control devices and installed in accordance with ASTM F 2090. The devices shall not require the use of keys or tools to operate.

R310.1.5 Replacement windows.

Replacement windows installed in buildings regulated by the International Residential Codeshall be exempt from the maximum sill height requirements of Section R310.1, including Subsections R310.1.1, R310.1.2, and R310.1.3, if the replacement window is the manufacturer's largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.

R310.1.5.1 Licensed facilities.

Windows in rooms used for foster care or day care licensed or registered by the state of Minnesota shall comply with the provisions of Section R310.1.5, or all of the following conditions, whichever is more restrictive:

1. Minimum of 20 inches (508 mm) in clear opening width;

2. Minimum of 20 inches (508 mm) in clear opening height;

3. Minimum of 648 square inches (4.5 square feet) clear opening; and

4. Maximum of 48 inches (1219 mm) from the floor to the sill height.

R310.2 Window wells.

The minimum horizontal area of the window well shall be 9 square feet (0.9 m2), with a minimum horizontal projection and width of 36 inches (914 mm). The area of the window well shall allow the emergency escape and rescue opening to be fully opened.

Exception: The ladder or steps required by Section R310.2.1 shall be permitted to encroach a maximum of 6 inches (152 mm) into the required dimensions of the window well.

R310.2.1 Ladder and steps.

Window wells with a vertical depth greater than 44 inches (1118 mm) shall be equipped with a permanently affixed ladder or steps usable with the window in the fully open position. Ladders or steps required by this section shall not be required to comply with Sections R311.7 and R311.8. Ladders or rungs shall have an inside width of at least 12 inches (305 mm), shall project at least 3 inches (76 mm) from the wall and shall be spaced not more than 18 inches (457 mm) on center vertically for the full height of the window well.

R310.2.2 Drainage.

Window wells shall be designed for proper drainage by connecting to the building's foundation drainage system required by Section R405.1 or by an approved alternative method.

Exception: A drainage system for window wells is not required when the foundation is on well-drained soil or sand-gravel mixture soils according to the United Soil Classification System, Group I Soils, as detailed in Table R405.1.

R310.3 Bulkhead enclosures.

Bulkhead enclosures shall provide direct access to the basement. The bulkhead enclosure with the door panels in the fully open position shall provide the minimum net clear opening required by Section R310.1.1. Bulkhead enclosures shall also comply with Section R311.7.8.2.

R310.4 Bars, grilles, covers and screens.

Bars, grilles, covers, screens or similar devices are permitted to be placed over emergency escape and rescue openings, bulkhead enclosures, or window wells that serve such openings, provided the minimum net clear opening size complies with Sections R310.1.1 toR310.1.3, and such devices shall be releasable or removable from the inside without the use of a key, tool, special knowledge or force greater than that which is required for normal operation of the escape and rescue opening.

R310.5 Emergency escape windows under decks and porches.

Emergency escape windows are allowed to be installed under decks and porches provided the location of the deck allows the emergency escape window to be fully opened and provides a path not less than 36 inches (914 mm) in height to a yard or court.

Emergency Escape and Rescue Openings Minnesota State Fire Code (MSFC) requirements MSFC requirements for emergency escape and rescue openings, otherwise known as egress windows, in sleeping rooms below the fourth story in residential occupancies (Group R and I-1) is broken down into three categories. 1. Existing occupancies when either: a. Constructed after July 1,1972. b. Licensed by State of Minnesota. c. Used as transient lodging. 2. New occupancies with sleeping rooms on main floor (level of exit discharge). 3. New occupancies with sleeping rooms in basements or above the main floor. Existing occupancies State Fire Marshal Division (SFMD) staff participated in an egress window study at a major window manufacturer in 2010 to determine the absolute minimum size that would be acceptable for occupants to safely egress and firefighters to enter for rescue in existing residential occupancies. The study led to an updated policy for licensed occupancies such as home daycares. This policy is now code language in the 2020 MSFC Section 1104.26. The minimum required opening for existing sleeping rooms on any level of the residence up to and including third floor is 4.5 square feet or 648 square inches. This PowerPoint or PDF will show how the measurements are taken to determine if the existing window opening complies with MSFC Section 1104.26. Window opening size not in compliance with MSFC Section 1104.26.2 shall be replaced with windows complying with the requirements for existing residential occupancies in MSFC Section 1104.26.6. In many cases a double hung or sliding window can be replaced with a casement insert and meet the requirements for egress windows. Where not required in existing residential occupancies  The sleeping room has a door directly to the exterior of the building.  Dwellings or structures constructed prior to July 1, 1972 (first state building code), provided they are not licensed by Minnesota or used for transient lodging.  Buildings protected throughout by an approved automatic fire sprinkler system.  Sleeping rooms of existing buildings having two separate and independent means of egress that pass through only one adjacent non-lockable room or area.  Hotels or motels constructed prior to April 11, 1983.

Windows under decks and porches Egress windows are allowed to be installed under decks and porches provided the location of the deck allows the egress window to be fully opened and provides a path not less than 36 inches in height to a yard or court. New construction or change in occupancy use New windows on the grade level main floor, known as the level of exit discharge (LED), need a window opening of 5 square feet. This PowerPoint or PDF show how to measure the opening size and maximum height above the finished floor. New windows above or below the LED need a window opening of 5.7 square feet. This PowerPoint or PDF show how to measure the opening size and maximum height above the finished floor and information on window wells for basement egress. SFMD policy on escape window opening height SFMD policy INS-04 allows escape windows with openings up to 52 inches off the floor. Those windows may meet the height requirement for existing buildings by:  Securing a step, platform or bed to the wall directly underneath the window o This step, platform or bed shall be no more than 44 inches below the opening and must be strong enough to support the weight of the person o The minimum acceptable width shall be the same as the window opening o The minimum acceptable depth away from the wall shall be 18 inches. SFMD policy on coverings on escape windows SFMD policy INS-04 allows plastic coverings to cover egress windows (and exterior doors) if the plastic covering meets the following requirements.  The plastic covering is transparent. The occupant can see rescuers outside and rescuers can see people on the inside.  The plastic covering may only be attached on the inside and can only be attached to the window frame or structure with two-sided tape, hook and loop (Velcro) or static cling.  The plastic shall have enough material overhanging the attachment on all sides, top and bottom to facilitate grabbing it from any direction and allow easy removal. SFMD policy on covers over window wells SFMD policy INS-04 allows window wells to be covered to keep them clear of debris, snow, and rain, and to help prevent people from falling in. The cover must comply with the following requirements:  The covering does not interfere with the opening of the window in any way.  The covering is supported so it cannot freeze to the ground, window well or structure. The covering is removable without the use of tools or special knowledge of the window well area by the building occupants. Developed December 2018 Updated September 2020