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Egress Window Installation in Thornton, CO
Adding a basement bedroom in Thornton? We size the window, the well and the cover to the City's current code, pull the permit and bring a structural engineer's sign-off.
Egress windows in Thornton
Basement Bedrooms That Pass in Thornton
Most Thornton homeowners call us for the same reason: they want a legal bedroom in the basement. A spare room for a growing family, a parent moving in, or a space to rent to a roommate all start with a proper escape window. Without one, the room can’t be counted as a bedroom, and it leaves the people sleeping downstairs without a safe second way out.
We take care of the whole job: concrete cutting, the window, the well, drainage, backfill and cleanup.
Old, undersized window wells are a common sight here, and we replace them often. If water tends to collect, we can add a sump pump or drain tap. For the window, consider a European Tilt and Turn.


Local know-how
A 1950s Start and a Code That Keeps Moving
Thornton was farmland until 1953, when developer Sam Hoffman began building on land off Washington Street, about seven miles north of Denver. By the end of 1955 the new community had about 5,500 residents in more than 1,200 homes, and it incorporated in 1956, named for then-Governor Dan Thornton. By 2020 the city had grown to nearly 142,000 people, so today the housing stock runs from those early streets to much newer subdivisions.
The City keeps its building code current. Thornton has adopted the 2024 International Residential Code, and its local amendments add a detail we watch closely: any grate, cover or screen over an escape opening or its well must release from inside without a key or tool and weigh no more than 30 pounds. The City’s basement finish sheet also calls for new bedroom wells to be at least 36 by 36 inches and says existing wells that don’t comply must be replaced.
Each basement bedroom gets its own escape window and well
New bedroom wells at least 36 in by 36 in
Grates and covers capped at 30 lbs and openable from inside
Undersized existing wells replaced, not patched
Engineering & permits
Working With Thornton's Building Inspection Division
In Thornton, residential permits and inspections are handled by the City’s Building Inspection Division at the Civic Center. Because the City now enforces the 2024 IRC with its own amendments, details like cover weight and well size get checked at inspection. We pull the building permit for you and line up the inspections. Each project also comes with a third-party structural engineering detail for the new opening, a follow-up inspection by a certified structural engineering firm and an approval letter. We provide that engineering on every job, even in places that don’t require it.
What we do in Thornton
Our services in Thornton
Egress window installation
Learn moreTilt & Turn windows
Learn moreWindow well replacement
Learn moreGrates & covers
Learn moreWindow well sump pumps
Learn moreWalkout basements
Learn moreThornton questions
Egress windows in Thornton: FAQ
Why does Thornton limit window well covers to 30 pounds?
Thornton’s amendments to the residential code say any bars, grilles, covers or screens over an escape opening or its well must open from inside without a key or tool and weigh no more than 30 pounds. A lighter cover is simply easier to push aside when someone needs to get out fast. We choose custom grates and covers that meet that limit.
My basement already has a window well. Can I keep it?
Often not, if the room will be a bedroom. Thornton’s basement finish sheet calls for new bedroom wells of at least 36 by 36 inches and says existing non-compliant wells must be replaced. Older wells are frequently too small. We measure yours during the estimate and recommend a replacement well only if it falls short.
How much should I budget for egress in Thornton?
The price is the same whether we enlarge an existing window or cut a fresh opening.
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Reviews
In our customers’ own words
“They installed 3 egress windows and they are great! Easy process with nice people.”
Lauren McClelland
“This is the 2nd house I have used Denver Egress with. We shopped the 2nd time and got many quotes. I shouldnt have bothered, pricing was the most fair. Great people, Gina, Sharine and the entire crew are professional and a pleasure to work with!”
M Swedlund
“Sales rep, install crew, and admin all worked well together to make my window install seamless. Window looks amazing and was done quickly. Thank you for your quality work and gentle price tag (<$5k for my situation).”
Libby McKenna
Planning a basement bedroom in Thornton?
Send a few details and a photo of the project area. We'll put together egress options for your Thornton home and a free estimate.
(720) 626-4221Serving Denver and the Front Range. Showroom and virtual appointments available.