Basement Bedroom Egress Windows in Denver
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Finishing a basement bedroom in the Denver metro means adding an emergency escape opening. Under the IRC (R319 in Denver's 2025 code), it needs at least 5.7 sq ft net clear, 24 in. high, 20 in. wide, and a sill no higher than 44 in. We cut the foundation, install the window and set the well. (2025 Denver Building Code)
Informational only. Your building department makes the final call.
When a basement room needs egress
The IRC requires at least one operable emergency escape and rescue opening in every sleeping room and in every basement with habitable space (2021 IRC R310.1; R319.1 in the 2024 IRC). Denver does not amend R319.1 in its 2025 code (2025 DBC). Centennial adds its own "sleeping room" definition: an enclosed habitable room that meets the R304/R305 room dimensions and has a closet, a closet-usable area, or space readily convertible to one (Ord. 2023-O-06).
What the opening and well must meet (strictest numbers)
- Net clear opening: at least 5.7 sq ft. This applies to every egress opening, including those at or below grade.
- Net clear height at least 24 in.; net clear width at least 20 in.
- Sill no higher than 44 in. above the floor.
- Window well: at least 9 sq ft, with horizontal projection and width each at least 36 in., and the window must open fully inside it.
- Well deeper than 44 in.: a ladder is required, and it may not encroach more than 6 in. into the well.
Section: R319 in Denver (2025 Denver Building Code) and the other 2024-IRC jurisdictions (Arvada, Thornton, Littleton, Englewood, unincorporated Jefferson and Adams counties); R310 where the 2021 IRC still applies (Aurora, Lakewood, Centennial, Douglas and unincorporated Arapahoe counties). Figures are the base IRC numbers in our verified code file (ICC). Local amendments outside Denver, Douglas County and Centennial have not been verified, so confirm with your building department.
Permits
In Denver, new window and egress window installations need a permit from Community Planning & Development (CPD). For other cities, see the permit guide and our free permit checklist.
Related
Services: Egress window installation · Window well installation · Basement egress cutting Guides: Egress window cost guide · Permit guide · Egress code guide · Egress window check Cities: Denver · Aurora · Lakewood · Arvada · Centennial · Basement bedrooms, rentals and ADUs
Frequently asked questions
Does every basement bedroom need its own egress window?
The IRC requires an emergency escape opening in every sleeping room (R310.1 in the 2021 IRC; R319.1 in the 2024 IRC). Plan on one per bedroom, and confirm with your building department.
How big does a basement bedroom egress window need to be?
At least 5.7 sq ft net clear, 24 in. high and 20 in. wide, with a sill no higher than 44 in. above the floor (IRC R319 / R310).
Does the window need a well?
A below-grade window needs a well of at least 9 sq ft, at least 36 in. in projection and width, and the window must open fully inside it. Wells deeper than 44 in. need a ladder.
Do I need a permit to add a basement egress window in Denver?
Yes. Denver CPD says new window and egress window installations require permits (CPD).