How to Plan Egress Windows

How to plan an egress window for greater safety, especially for basement remodels.

By Spike Carlsen

From The Family Handyman

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About This Project

Overview and Preparation

Step-by-Step Instructions and Pictures of How to Plan Egress Windows

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Few of us think of windows as lifesaving equipment—but they are! When you need to escape a house fire or other disaster, or when rescue personnel need to enter—the right-sized egress window can make the difference between life and death.

NOTE: HEIGHT × WIDTH OF UNOBSTRUCTED OPENING MUST EQUAL AT LEAST 5.7 SQ. FT.

The old saying “Always leave yourself an out” is especially true when it comes to home fires. When the basement stairs are blocked by a flaming television (true story), or fire and thick, black smoke are racing down a hallway toward a dead-end bedroom, windows that are large enough for you to escape—and for firefighters to enter—become essential lifesaving equipment. These all-important escape hatches are called egress windows.

The purpose of this article is threefold:

To inform you why and where you need egress windows and how big they should be.
To alert you to the fact that, by today’s standards, your bedrooms and basement may very well not have proper-sized egress windows.
To help you choose the right egress windows and their placement as you build and remodel.

Egress Window Codes and Logic
Basement egress windows and the window well both have to meet rigorous requirements that allow occupants to escape and rescue personnel to enter.

You may have installed smoke detectors, but if you haven’t provided a way out once they blare, you’ve only done half the job. This is especially true for upstairs bedrooms and basements, where the stairway is often the sole escape route. If that stairway is blocked, you can be trapped.

According to the International Building Code, “Basements and sleeping rooms below the fourth story shall have at least one exterior emergency escape and rescue opening. . . . Such opening shall open directly into a public street, alley, yard or court.” This “escape and rescue opening” can be a window, skylight or patio door, but it must meet certain criteria:

It must have a minimum net clear opening of 5.7 sq. ft. Net clear opening refers to the actual free andclear space that exists when the window is open. It is not the rough opening size or the glass panel size or anyother size, but the actual opening aperson can crawl through. Code officials want the opening large enough so firefighters can comfortably crawl through the window in full protective gear with an oxygen tank on their back. Ground-floor windows only need a net clear opening of 5 sq. ft.; they can be smaller because a rescue ladder doesn’t take up part of the opening.
The opening height must be at least 24 in., and the opening width must be at least 20 in.
The bottom of the clear opening must be within 44 in. of the floor.
The window or other opening must be operational from the inside without keys or tools. Bars, grilles and grates over windows must be operational without tools or keys and still allow the minimum clear opening.

Note that a window opening that’s the bare minimum of 24 in. high and 20 in. wide does not meet egress requirements, since its net clear opening is only 3.33 sq. ft. A window has to be taller and/or wider than these minimums to meet the 5.7-sq.-ft.-opening requirement.

All these numbers may seem daunting, but selecting a new egress window doesn’t need to be. Window manufacturers list the net free opening of their windows and skylights in their catalogs, and whether they meet egress requirements.