Basement Egress Window Guide: Codes, Costs, and Installation

An egress window is required by the International Residential Code (IRC) in any bedroom located in a basement. Without one, the basement legally cannot be used as a bedroom — and without a legal bedroom, your finished basement adds less value to the home and may fail inspection at resale. Here is what egress windows cost, what the code requires, and how installation works.

What Is an Egress Window?

An egress window is an emergency exit window large enough for a person to climb out of in case of fire or other emergency — and for a firefighter to enter. Basements are below grade, which means a standard basement window does not meet egress requirements without specific sizing and a window well large enough to allow exit.

Any basement room used as a sleeping area legally requires one. Most jurisdictions also require egress for any room used as a habitable space (living room, home office, bonus room), though requirements vary by local code.

IRC Egress Window Requirements

The International Residential Code (Section R310) sets these minimum requirements. Local codes may be stricter — always verify with your municipality before ordering windows.

Requirement	Minimum
Net clear opening area	5.7 square feet (grade-floor windows may be 5.0 sq ft)
Net clear opening height	24 inches
Net clear opening width	20 inches
Maximum sill height	44 inches from finished floor

Net clear opening means the usable space when the window is fully open — not the rough opening or the window frame size. A window marketed as “egress-sized” should specify the net clear opening dimensions, not just the overall unit size.

The window must be openable from the inside without tools or special knowledge.

Window Well Requirements

Below-grade egress windows require a window well — a semicircular or rectangular excavation that allows the window to open and provides a landing area.

• Minimum clear dimensions: 36 inches wide x 36 inches projected from the wall (some codes require 36x44 or larger)
• If the well depth exceeds 44 inches: A permanently attached ladder or steps must be provided
• Cover: Window well covers are allowed and recommended but must be openable from the inside without tools

A well that is too small — even if the window meets size requirements — can fail inspection.

What Egress Window Installation Costs

Cost varies by existing conditions, window type, and local labor rates.

Component	Cost Range
Egress window (casement or double-hung)	$200 - $800
Window well (galvanized steel or polycarbonate)	$150 - $500
Excavation and concrete cutting	$500 - $1,500
Waterproofing and drainage at well	$200 - $600
Installation labor	$800 - $2,000
Total installed cost	$2,000 - $5,500

Factors that push costs higher:

• Thick poured concrete foundation (harder to cut than block)
• Proximity to underground utilities (requires utility locates before excavation)
• Depth of excavation (deeper requires more soil removal and potentially a well ladder)
• Finishing work inside (window trim, drywall patching around new opening)

Types of Egress Windows

Not all window types work for egress. The window must be openable from the inside without tools and must achieve the minimum net clear opening.

Casement Windows

• Open outward on a hinge (like a door)
• Most commonly used for egress because the entire frame area is the opening
• Easy to reach minimum net clear opening in a smaller overall unit size
• Cost: $250 - $700 installed (window only, not excavation)

Single-Hung and Double-Hung Windows

• Slide vertically
• Only the operable sash counts toward net clear opening (typically the bottom half for double-hung)
• Requires a larger overall unit to achieve egress dimensions
• Cost: $200 - $600

Slider Windows

• Slide horizontally
• Only half the total width counts toward net clear opening
• Requires a wide window to achieve egress requirements
• Less common for egress than casement

In-Swing Casements

• Open inward — allowed in some jurisdictions, prohibited in others
• Can conflict with furniture placement
• Verify local code before selecting

The Installation Process

1. Permit pulled — Egress window installation requires a building permit in virtually every jurisdiction. Your contractor should pull it; if they offer to skip this, find a different contractor.
2. Utility locates — Call 811 (US) before any excavation. Marking is free and required by law.
3. Excavation — The well area is dug out to the required depth and width.
4. Concrete cutting — A diamond blade saw cuts the foundation opening. For block foundations, block is removed. For poured concrete, core drilling or saw cutting is used.
5. Window framing and installation — The window is set in the new opening, leveled, and secured. The frame is flashed and sealed.
6. Window well installation — The steel or polycarbonate well is anchored to the foundation and backfilled.
7. Drainage — Gravel is placed at the base of the well with a drain or direct connection to the drain tile system to prevent well flooding.
8. Inspection — The permit inspection confirms the window meets code. This is required before the permit is closed.

Waterproofing the Egress Window Opening

Any penetration through the foundation wall is a potential water entry point. A properly installed egress window includes:

• Flashing at the top and sides of the opening
• Sill pan to capture water that enters the window frame and direct it out
• Sealed gap between the window frame and the foundation (expanding foam, then caulk or mortar)
• Window well drain — either a gravel bed draining through the footing, or a direct connection to the interior drain tile system

Poorly installed egress windows are a common source of basement water intrusion. If you are adding egress to a basement that otherwise has no water problems, insist on proper flashing and drainage.

Choosing a Contractor

Egress window installation is typically done by:

• Window installation companies that specialize in egress
• General contractors with masonry and concrete experience
• Basement waterproofing companies (often do egress as part of finishing packages)

Get at least three quotes. Verify that the contractor will pull the permit. Ask specifically who handles the permit inspection and what happens if the window fails inspection.

Do not hire based on price alone — a poorly cut or improperly flashed opening can cause structural and water damage that costs far more to fix than the original installation.

FAQ

Is an egress window required for a basement bedroom? Yes. IRC Section R310 requires a code-compliant egress window in any basement room used as a sleeping area. Without one, the room legally cannot be called or marketed as a bedroom.

How much does it cost to install an egress window in a basement? Total installed cost typically runs $2,000 - $5,500, depending on foundation type, excavation depth, window choice, and local labor rates. Get itemized quotes that separate the window, excavation, and labor.

Can I install a basement egress window myself? The window installation itself is within reach of experienced DIYers. The concrete cutting requires specialized equipment (diamond blade saw or core drill) that most homeowners will rent or contract out. A building permit and inspection are required regardless — you cannot skip the permit even if you do the work yourself.

What is the minimum size for a basement egress window? IRC minimum is 5.7 square feet of net clear opening, with minimum dimensions of 24 inches high and 20 inches wide. The sill cannot be higher than 44 inches from the finished floor. Net clear means the usable opening when the window is fully open.

How long does egress window installation take? Typically 1 - 2 days for the full installation — excavation, cutting, and window installation on day one, drainage and cleanup on day two. The permit inspection may be scheduled separately.

Do I need a window well cover? It is strongly recommended but not universally required. Covers keep out rain, debris, and animals. They must be openable from the inside without tools to meet code. Clear polycarbonate covers allow natural light while providing protection.