An egress window is not a specific style or design of a window. An egress window is a window that is of a minimum size, positioned at a minimum height off the floor that allows the occupants of a room to easily exit the room through the window in the event of fire or other emergency. Egress windows are part of most municipal building codes.
Figure 1 - Attractive egress window in basement
However, homeowners should not consider the need to have egress windows as another intrusive government regulation. Egress windows are designed to save the lives of your family and guests and should be considered to be something that you want, not something you must have!
What rooms in a home require egress windows?
- Any room in a home, on any floor, including the basement that is used as a bedroom, or a room where it is common for someone to sleep.
- Finished basement areas where the space is designed to be occupied. If a room or multiple rooms in a finished basement are used as bedrooms they must have their own egress windows.
What are the minimum requirements for an egress window?
The IRC (International Residential Code) states that an egress window must meet the following requirements:
- The clear opening must be a minimum width of 20 inches.
- The clear opening must have a minimum height of 24 inches.
- The clear opening on all floors but the ground floor must be a minimum of 5.7 sq. ft.
- The clear opening on the ground floor must be a minimum of 5 sq. ft.
- The maximum height off the floor to the top of the window sill shall not exceed 44 inches.
- The occupant of the room must be able to open the window from the inside without the use of any special tools or keys.
Note: The definition of
clear opening is the unencumbered space available to exit the room. It is not the physical dimensions of the glass in the window nor is it the rough opening that the window frame was installed in.
Note: Grilles, bars and grates may be installed on the interior or exterior of the window, but they must be removable or be able to be opened without the need for special tools or keys and must not encumber the window’s minimum clear opening requirements.
Note: A window that is 20 inches wide by 24 inches high would appear to meet the IRC requirements for an egress window, however it doesn’t as the minimum free opening must be 5 sq. ft. on the ground floor and 5.7 square feet on all other floors. A window that is 20 inches wide by 24 inches high is only 3.3 sq. ft. To meet the requirements of the IRC, a 20 inch wide window must be 42 inches high and a 24 inch high window must be 34 inches wide.
Caution: Always check your local building codes to ensure that requirements for egress windows have not changed since the publication of this article.
What type and style of window should be used as an egress window?
The IRC does not specify a window type or style. However casement windows are an excellent choice providing they swing clear of the window frame.
Note: With basement egress windows it is necessary to ensure that the person can actually exit the building through the window this may require the use of specially designed and/or constructed earth retaining walls or specially designed egress area walls as shown in Figure 2 and 3.
Figure 2 - Galvanized egress window well
Figure 3 - Molded egress window well with ladder and drain
Figure 4 - Egress window below a deck
The IRC rules for window wells or free space beyond the window are:
- The egress opening must not be less than the free opening space of the window and cannot encumber the ability to open the egress window to its fullest extent.
- The well on the exterior of the window must be a minimum of 36 inches in both length and width for a minimum of 9 sq. ft.
- If the depth of the window well is more than 44 inches a ladder must be installed in the window well. The IRC requirements for the ladder are that it must be a minimum of 12 inches wide and it cannot project less than 3 inches from the wall of the window well. As well, the ladder cannot be placed in a position that makes its access difficult when the egress window is in the fully opened position. The ladder in the window well cannot make the window well opening less than 30 inches.
- In many cases an egress window may be covered by a porch or deck. If this situation occurs, the IRC regulations require that the measurement from the top of the window well to the bottom of the deck or porch joists not be less than 48 inches, as shown in Figure 4.
Your current windows may not meet IRC egress requirements.
There is no legislation, to my knowledge anywhere in North America that requires that older homes constructed prior to the IRC egress window requirements be upgraded. As well, an earlier for egress windows only required that the opening be 5 sq. ft.
The problem often arises when remodel work is done without building permits and basements, attics and other rooms are converted into bedrooms or living space. As an example, a den converted into a bedroom requires a window that meets the IRC requirements for egress. Whereas when it was a den it didn’t have the egress window requirement.
It should also be pointed out that not meeting the IRC egress requirements can also inadvertently occur when older windows are replaced with new modern energy saving windows of a different style. As an example, replacing a casement window which meets the egress requirements with a hung window, in the same rough window opening, that because of the way the hung window opens it no longer meets the IRC egress requirements.
Note: In some jurisdictions, when major remodel work is being done to a house, there is a requirement that the house be brought up to code even in areas that may not be part of the remodel. This could involve installing egress windows in all bedrooms, as well as providing an egress window in a basement or attic.
What is the best method to install an egress window in older construction?
If you face the situation where you want to or are required to replace an old window with an egress window the easiest and most efficient method is to make the window sill lower, providing the window is at least 20 inches wide. The reason for this is the method of window framing used in construction. The framing below a window is not load bearing and can easily be removed and lowered without affecting the structural integrity of the wall. If you make the window wider you are working on load bearing portions of the buildings structure. This means you would be facing much a more complex construction program and that means more expense.