Egress Windows

Outdoor shot of an egress window.When considering basement renovations, you must also account for all applicable local building codes. If any habitable spaces or bedrooms are being constructed in your basement, then an appropriate “means of egress” will be required by both International Residential Code R310 and Ohio Residential Code 4101:1-10.


Egress defined simply means an exit or a means of exiting from an enclosed place. Residential codes mandate that egress windows are required in the event that any habitable rooms are constructed in a basement. Furthermore, where basements contain one or more sleeping rooms, emergency egress 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 yard. The main purpose of these codes are to ensure that adequate escape routes are in place in the event of emergency situations such as fires, while also providing rescue personnel a way to enter the lower level of your home.


Residential codes also set minimum requirements for the size and dimensions of egress windows. These requirements are in place to ensure proper clearance through your means of egress and are listed below:


  • Egress openings minimum net clear opening: 5.7 square feet (this must be achieved as a result of the normal operation of the opening).
  • Egress maximum sill plate height from floor: 44 inches (when code mandates that an egress window needs to be installed with a finished sill height below the adjacent ground level, which will be the case in most basements, then a Window Well will be required as well in accordance with code).
  • Egress minimum net clear opening height: 24 inches
  • Egress minimum net clear opening width: 20 inches (an egress opening of minimum size requirements will not meet code as a window measuring – 20″w x 24″h – will only result in an egress opening of 3.34 sq. ft. Openings measuring 20”w x 42”h or 35”w x 24”h will fall within code as they will both result in net clear openings of 5.84 sq. ft.
  • Egress openings must be operational from the inside of the room without the use of keys or any special tools.


Casement windows are an excellent option for “means of egress” as they crank to swing open taking up a minimal amount of wall space while still meeting code requirements.


Aside from providing a safe exit in emergency situations, egress windows can transform the “look and feel” of your basement. The dark and dank basement issue is resolved with the increase of natural light and airflow creating additional comfortable, habitable, and safe square footage to your home while increasing its value at the same time.