Thornton, Colorado
Window Well Replacement in Thornton, CO
Thornton spells out exactly how big a basement window well has to be, and older wells may not measure up. If you're finishing a basement, adding a bedroom or just tired of a rusty well, Denver Window Wells provides window well replacement in Thornton that's sized and installed to code.
Why Thornton Window Wells Often Fall Short
Thornton was founded in 1953, so some neighborhoods have homes whose basements and window wells have been in the ground for decades. Thin steel wells rust and bend with age, and some are smaller than today's requirements. Thornton's basement guide is clear on this point: if an existing well doesn't meet current size rules, it has to be replaced when a new bedroom is added.
The ground adds its own pressure. Expansive clay, which the Colorado Geological Survey says can swell up to 20 percent when wet, pushes against wells after spring storms and snowmelt. Freeze-thaw cycles do the rest, loosening seams and tipping wells away from the foundation until water finds its way to the basement window.
Too small for code
The well is narrower than 36 inches in either direction or smaller than 9 square feet.
Missing ladder
A well deeper than 44 inches has no ladder or steps, so climbing out would be difficult.
Rust holes
The steel has rusted through near the bottom, letting gravel and soil spill into the well.
Basement dampness
You notice musty smells or damp spots near the basement window after rain or melting snow.
Window Well Replacement Options for Thornton Basements
Every option below can be sized to meet Thornton's basement window well requirements.
Boman Kemp Window Wells
Boman Kemp wells come in sizes that meet the 9 square foot and 36 inch minimums, with ladder options for deeper Thornton basements.
Boman Kemp window wells
Rockwell Window Wells
Rockwell stone-look composite wells give you the size you need while adding a finished, natural look around your Thornton basement window.
Rockwell window wells
Timber Window Wells
Custom timber wells can be built wide and terraced, which helps deeper Thornton wells meet the size rules while adding plenty of daylight.
Timber window wells
Window Well Sump Pumps
When a well collects water, a sump pump or improved drainage keeps it off the window, which matters even more once the basement is finished.
Window well sump pumps
Egress Window Installation
Adding a basement bedroom in Thornton? We install the egress window and a code-compliant well together, with the permit taken care of.
Egress window installation
Covers, Grates and Locks
Covers, grates and locks keep snow and debris out, and we'll recommend options that still let the window work as an exit.
Window well coversThornton Basement and Window Well Rules
Thornton adopted the 2024 International Residential Code effective July 1, 2026, and the city requires permits for window replacement and new windows. That includes projects that add an egress window to a basement, so the window and its well need to meet current code from day one.
Thornton's basement guide also covers the well itself: at least 9 square feet in area, at least 36 inches in each direction, and a ladder when the well is deeper than 44 inches. If an existing well doesn't meet those numbers, it must be replaced when a new bedroom is created in the basement.
We take care of planning and permits for our work. During your free estimate, we'll measure your current wells and confirm what your Thornton address requires for your window well replacement. If a well needs to grow to meet the size rules, we'll explain the options before any digging starts.
Before You Finish
Finishing a Thornton Basement? Start With the Wells
Window well rules are easy to overlook when you're planning a basement bedroom. Since Thornton requires an undersized well to be replaced when a new bedroom is added, it pays to check the wells first. That way the egress window, well, ladder and cover can be planned together instead of becoming a surprise halfway through the project.
Thornton homes also face the same Front Range weather as the rest of the metro: wet spring storms, snowmelt and freeze-thaw. Pairing a properly sized well with good drainage protects both the new room and the window. A sturdy cover adds one more layer, keeping snow and leaves from piling up in the well over the winter.
Thornton at a Glance
- Founded1953
- Building code2024 IRC (effective July 1, 2026)
- Window permitsRequired for window replacement and new windows
- Minimum well size9 sq ft, at least 36 in. each direction
- LadderRequired when the well is deeper than 44 in.
How Window Well Replacement Works
1
Free estimate
Call or send photos of your wells. We measure, check drainage and talk through options and pricing.
2
Planning and permits
We take care of planning and any permits your project needs before work starts.
3
Remove and replace
We dig out the old well, set the new one to your foundation and add gravel for drainage.
4
Finish and clean up
Covers, ladders or grates go on, and we backfill and clean up so your yard looks finished.
Thornton Window Well Replacement: Your Questions Answered
How big does a window well need to be in Thornton?
Thornton's basement guide calls for a well of at least 9 square feet that measures at least 36 inches in each direction. Wells deeper than 44 inches need a ladder. We size every replacement to meet those rules.
Do I have to replace my window well to add a basement bedroom in Thornton?
If the existing well doesn't meet Thornton's size requirements, yes. The city requires it to be replaced when a new bedroom is added. We can check your wells and include the replacement in your project.
Does Thornton require a permit for new windows?
Yes. Thornton requires permits for window replacement and new windows, including egress windows. We handle the permit for our work and confirm what a well-only replacement needs during your estimate.
Can I put a cover on an egress window well?
Yes. We'll recommend covers and grates for egress wells that keep the window usable as an exit while keeping out snow, leaves and debris.
Need Window Well Replacement in Thornton?
Call (720) 675-9339 to schedule a free estimate. Financing is available on approved credit.
Window Well Replacement in Areas Around Thornton
We also work in these nearby communities.