Do You Need an Egress Window in Your Basement?
Last updated
If you are adding a bedroom in the basement, yes: under the 2024 IRC every sleeping room needs at least one emergency escape and rescue opening.
Informational only. Your building department makes the final call.
The short answer
- Adding a bedroom in the basement? Yes. Under the 2024 IRC, every sleeping room needs at least one emergency escape and rescue opening, and new sleeping rooms created in an existing basement must have one (Jefferson County, R319.1 and R319.7).
- Finishing a basement with no bedroom? Under the 2024 IRC text Jefferson County publishes, other basement alterations or repairs do not trigger an escape opening (R319.7). Older code text restated by Arapahoe County (2021 IRC) says basements that are finished or partly finished need one. Which rule applies depends on the edition your jurisdiction has adopted, so check before you plan.
- Basement already has a window? An existing operable window may be accepted if it meets the alteration provisions (R319.7 exception, Jefferson County). Douglas County's guide lists existing-window minimums of 4 sq ft and 22 × 20 in (Douglas County hub).
What a compliant opening must meet
- Net clear opening of at least 5.7 sq ft.
- Clear opening at least 24 in high and 20 in wide, reached by normal operation of the window or door.
- Bottom of the opening no more than 44 in above the floor.
- Operable from inside without keys or tools, opening to a public way or a yard or court that leads to one. Source: 2024 IRC R319 as published by Jefferson County Building Safety; the same numbers appear in the 2021 IRC R310 restated by Arapahoe County.
Window wells
Area wells deeper than 44 in need a permanently fixed ladder or steps that the open window doesn't block (Jefferson County, R319.4.2). Arapahoe's guide lists a well of at least 9 sq ft with a 36 in minimum dimension (Arapahoe).
Permits
Egress windows need a permit in Denver (Denver CPD) and unincorporated Jefferson County (Inside the Home). See the Denver metro permit guide for each jurisdiction.
Related
- Egress window check: see if your window and well likely meet the minimums Basement bedrooms, rentals and ADUs · Egress window vs. egress door · Egress code guide
Services
Egress windows · Window wells · Covers · Basement egress · Code guide
Frequently asked questions
Do I need an egress window if I'm adding a basement bedroom?
Yes. Under the 2024 IRC, every sleeping room needs at least one emergency escape and rescue opening, and new sleeping rooms created in an existing basement must have one.
Do I need one if I'm finishing a basement with no bedroom?
It depends on the code edition. Under the 2024 IRC text Jefferson County publishes, other basement alterations do not trigger an escape opening (R319.7). Older 2021 IRC text restated by Arapahoe County says finished or partly finished basements need one.
My basement already has a window. Does it count?
An existing operable window may be accepted if it meets the alteration provisions (R319.7 exception). Douglas County's guide lists existing-window minimums of 4 sq ft and 22 × 20 in.
What must a compliant opening meet?
Net clear opening of at least 5.7 sq ft; clear opening at least 24 in high and 20 in wide; bottom of the opening no more than 44 in above the floor; operable from inside without keys or tools.
Does a deep window well need a ladder?
Yes. Area wells deeper than 44 in need a permanently fixed ladder or steps that the open window doesn't block.