Window Replacement

Replacement Windows


A Permit is required for all window installations and replacements.

Replacement Windows (R310.2.5) 

Replacement windows installed in buildings meeting the scope of this code shall be exempt from the maximum sill height requirements of Section R310.2.1 and the requirements of Section R310.2.2, provided that the replacement windows meet the following conditions:

  1. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window is of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
  2. The replacement window is not part of a change of occupancy.

Sections R310.2.1 and R310.2.2 mentioned in the first paragraph are requirements for the size of egress windows (windows in sleeping rooms).

This says that a new window of the same style (casement, double hung, slider, etc.) can be installed if it is the largest window of that style that fits in the rough opening

If you change styles of the window, the actual clear opening (when the window is opened) must be the same or larger than the existing window.

The intent of the code is that the new window opening should be as large as or larger than the one replaced.

Window Wells For Egress Windows

When the finished sill height of an egress window is below the exterior grade, a window well shall be provided and shall comply with the following:

  1. The minimum area of the window well shall be 9 square feet, with a minimum horizontal projection and width of 36 inches. The area of the window well shall allow the egress window to be fully opened. 
  2. Window wells with a vertical depth greater than 44 inches shall be equipped with a permanently affixed ladder or steps, usable with the window in the fully open position. Ladders or rungs shall have an inside width of at least 12 inches, shall project at least 3 inches from the wall, and shall be spaced not more than 18 inches on center vertically for the full height of the window well. The ladder or steps shall be permitted to encroach a maximum of 6 inches into the required dimensions of the window well. 
  3. If a driveway or sidewalk is within 36 inches of any edge of the window well, a guardrail shall be place on two sides of the window well. Guardrails shall not be placed on the same side of a window well as the ladder or steps.
  4. Window wells are not allowed to encroach into any drainage or utility easement or into the required building setbacks. 

All window wells require a drain unless in Class I well-drained soil. 

See Related Documents for an example of a window well opening.