Egress Window Know-How
The current International Residential Code (IRC) requires all finished basements and basement bedrooms, to have two ways out. The first being the normal basement steps to the first floor, and the second being an emergency-egress widow or door to the outside permitting occupants two ways to escape and allowing a fully outfitted firefighter two ways to enter during a fire emergency.
International Residential Code (IRC)
- Minimum width of clear opening: 20 inches
- Minimum height of clear opening: 24 inches
- Minimum net clear opening: 5.7 sq. ft. (5.0 sq. ft. for ground floor Windows)
- Maximum sill height above floor: 44 inches – Target 42 inches
Let’s do the math:
- 20 in. x 24 in. clear opening = Only 3.3 sq. ft.
- 20 in. x 42 in. clear opening = 5.8 sq. ft.
- 35 in. x 24 in. clear opening = 5.8 sq. ft
How to measure an egress windows clear opening:
Types of Egress Windows
Standard Double Hung Window: Pro’s – Many inexpensive Windows are available; Con’s – Windows need to be large to meet IRC code, limited or no warranty
Casement Outswing Window: Pro’s – Many inexpensive Windows are available; Con’s – Usually not made with egress hinges, many don’t open 90 degrees, requires the use of wider widows and wells, could interfere with well covers if the window is partially above top of the well, limited or no warranty
Standard 48” Sliding Basement Window: Pro’s – Many inexpensive 3 ¼” jamb depth Windows are available; Con’s – Most 48” wide windows don’t meet the IRC 20” minimum clear opening requirement, limited or no warranty
Egress 48” Sliding Basement Window: Pro’s – 8” to 12” jamb depths, meets IRC 20” clear opening requirement, meets Energy Star requirements, 10 year warranty; Con’s – more expensive
Single Hung In-swing Window: Pro’s – Uses egress hinges, dual function, takes a much smaller window to meet the 5.7 sq. ft. IRC requirement, 20 year warranty, works in a small compact well, no issues with cover interference; Con’s – More expensive
Casement In-swing Window: Pro’s – Uses egress hinges, smallest window to meet 5.7 sq. ft. IRC requirement,
20 year warranty, works in a small compact well, no issues with well cover interference; Con’s – More expensive
EGRESS WINDOW WELL KNOW-HOW
Egress Window Wells/Area Wells:
Required where window sill height is below ground elevation.
Horizontal projection: = 36 inches minimum
Vertical width: = 36 inches minimum
Minimum surface area = 9 sq. ft. (width x projection)
Required on window wells deeper than 44″ and must be permanently attached. Ladder may encroach into well up to 6″.
Maximum step distance between rungs: = 18″
Rungs: 12″ wide or greater and must project a minimum of 3″ away from wall but no more than a maximum of 6″
Grates / Covers:
Shall be removable without special tools.