What Are the Minimum Measurement Requirements for an Egress Window?

IRC Measurement Requirements

• The IRC-2000 standards require that all bedrooms in a home have an egress window that meets the following requirements: The windows must have an opening width of at least 20 inches and an opening height of at least 24 inches. The minimum clear opening size required is 5.7 square feet or 5 square feet on ground floors. The maximum height the sill can be above the floor is 44 inches.

Basement Egress Windows

• Egress windows for basement bedrooms may need to meet additional requirements, including the following: The window wells must allow full opening of the window, and there must be a floor area of 9 square feet with a minimum width of 36 inches and a minimum length of 36 inches. If the depth of the window well is more than 44 inches, the window must have an attached ladder or steps. For a ladder, its width must be at least 12 inches, it must extend at least 3 inches from the window well, the open window cannot interfere with the ladder, and the ladder cannot intrude on the required dimensions of the window well by more than 6 inches. If an egress window is under a porch or deck, the distance between the top of the window well and the bottom of the porch or deck joists must be at least 48 inches.

Types of Windows

• Different types of windows can meet these egress window requirements. Casement windows are a good choice, especially for basements, according to Service Magic. Casement windows don't take up much wall space, and they have side hinges and wide openings, making escape easy. Double-hung or glider windows can work if they are big, taking into account that the glass occupies half of the opening. However, awning windows may not work well and may make escape more difficult, especially in basements because these windows open outward from the bottom.

Considerations

• If you are replacing a small window with a larger one, making the height of the window opening larger takes less structural work than making the width larger, according to Home Safety Solutions. While increasing the height of the window opening often only takes lowering the height of the sill below the window, increasing the width of the opening typically involves the major project of installing a larger and sturdier horizontal structural header over the window opening.