Egress Window Sizes Chart for Colorado: Dimensions That Meet Code

Egress Window Sizes Chart for Colorado: Standard Dimensions

Colorado's International Building Code (IBC) and local Denver amendments set specific minimum requirements for egress windows in basements and sleeping rooms. If you're converting a basement into a bedroom, finishing a family room with sleeping potential, or simply want to meet current code for resale value, understanding egress window sizes is essential.

Here's what you need to know: minimum net clear opening of 5.7 square feet (or 5 square feet in existing structures), with minimum width of 20 inches and minimum height of 24 inches. The sill (bottom edge) must be no higher than 44 inches from the floor. These aren't suggestions—they're legal requirements in Colorado that protect occupants during emergencies.

Standard Egress Window Sizing Chart

Important: Net clear opening is the actual passable space when the window is fully open—not the frame size. When you're shopping or getting quotes, always confirm this measurement with your contractor. The difference between rough opening and net opening catches many homeowners off guard.

Colorado-Specific Considerations for Egress Window Installation

Denver and the Front Range present unique challenges that affect egress window sizing and well design:

• Clay and expansive soils: Colorado's native clay expands when wet and shrinks when dry. Window wells in metro Denver must account for seasonal movement. Proper compaction, drainage, and well depth are non-negotiable.
• High elevation and weather extremes: Denver's 5,280-foot elevation means UV exposure is intense, and temperature swings from –20°F to 90°F+ stress window seals. Egress windows must be rated for these conditions.
• Basement water intrusion: Spring snowmelt and hail season (May–July) drive moisture problems. A poorly sized or installed window well becomes a water entry point. At Affordable Egress Co., we've completed thousands of installs across the Denver metro since 1999—water management is built into every job.
• Frost depth: Colorado's frost line averages 36–48 inches, depending on location. Window wells must be dug deep enough to account for freeze-thaw cycles without destabilizing your foundation.

Window Well Depths and Sizing for Denver Basements

The window well is as important as the window itself. Standard depths vary:

• Typical well depth: 36–48 inches (below grade/soil level)
• Well width: 10–16 inches minimum (allows 6 inches clearance on each side of window)
• Well length: varies with window width (typically 6–12 inches beyond window frame)

In Denver's clay-heavy soils, deeper wells (closer to 48 inches) perform better long-term. Shallower installations around 36 inches work in some Front Range locations with sandy soil. Your contractor should assess your specific lot before finalizing dimensions.

We always recommend a window well cover or grate—not just for safety, but to keep debris and water out. Denver's hail and heavy spring rains test every installation.

Do You Need to Upgrade Your Current Window Size?

If your basement has old, non-compliant windows, or if you're planning a bedroom conversion, you may need to go larger. Here's the practical question: Can your basement wall accommodate a larger rough opening?

If you're limited by wall space, structural posts, or HVAC ducts, here's the good news: casement and awning-style windows open outward, giving you more net clear opening in a smaller frame. A 28" × 40" casement window often meets code where a 24" × 36" slider falls short.

This is where a professional assessment pays off. Affordable Egress Co. handles the full scope—from concrete cutting (we do our own, no subcontractors) to framing, window installation, and well finishing. Most jobs are completed in a single day. We also provide free estimates, so you'll know exactly what you're looking at before any commitment.

Next Steps: Ensure Your Egress Window Meets Colorado Code

Using this egress window sizes chart as a starting point, verify your specific window dimensions against your local Denver or county building department code (some Front Range towns have minor variations). If you're planning a basement bedroom or remodel, confirm that your existing windows—or proposed windows—actually meet the net clear opening requirement, not just the frame size.

Affordable Egress Co. has been the Denver metro's trusted egress specialist for over two decades. We understand Colorado soils, Front Range weather, and the exact dimensions and installation methods that pass inspection the first time. If you'd like a professional assessment of your basement or a quote on an egress window installation or window well project, we're here to help.