Window Well Installation & Replacement in Denver
Last updated
A below-grade egress window needs a well outside it. Under IRC R310.2.3, the well must be at least 9 sq ft, with horizontal projection and width each at least 36 in., and the window must open fully inside it. Wells deeper than 44 in. need a ladder. We dig, set and backfill the well. (IRC R310.2.3)
What it involves
A well keeps soil back from a below-grade window. Under IRC R310 an egress well needs at least 9 sq ft with a minimum dimension of 36 in, and a ladder when it is deeper than 44 in (Arapahoe County summary of IRC R310).
Code basics
Min. 5.7 sq ft net clear opening (5 sq ft at grade/below grade), 24 in clear height, 20 in clear width, sill no more than 44 in (Arapahoe County / IRC 2021 R310). Full details: code guide.
Permits
Denver requires a permit for new egress windows (source). Landmark/historic properties also need design review (source).
Related guides
- Egress window check: see if your window and well likely meet the minimums Topping the well? Read our window well cover options and the well size and ladder rules, or see egress window installation. Not sure you need one? See when a basement needs an egress well, wells for rental and ADU bedrooms and a door instead of a window and well.
FAQ
- How much does it cost? → cost guide
- Do I need a permit? → Yes in Denver; see the code guide.
Frequently asked questions
What does a window well do?
A well keeps soil back from a below-grade window.
How big does an egress window well need to be?
Under IRC R310 an egress well needs at least 9 sq ft with a minimum dimension of 36 in, and a ladder when it is deeper than 44 in.
How big must the egress window itself be?
At least 5.7 sq ft net clear opening (5 sq ft at grade/below grade), 24 in clear height, 20 in clear width, with a sill no more than 44 in above the floor (IRC 2021 R310, as restated by Arapahoe County).
Do I need a permit in Denver?
Yes. Denver requires a permit for new egress windows, and landmark or historic properties also need design review.
When does an egress window well need a ladder?
Under IRC R310.2.3.1, a ladder is required when the well is deeper than 44 in. The ladder may not encroach more than 6 in. into the required well dimensions. Some jurisdictions amend well rules (Douglas County allows a 24 in. projection in some existing homes), so check your city.