Egress Window Requirements for Idaho Basement Bedrooms
By Carter Built Construction · Updated July 12, 2026
If you're finishing a basement in Idaho and want the new rooms to legally count as bedrooms, egress is the code requirement that matters most. Here's what the residential code Idaho jurisdictions follow actually requires, in plain English.
The core egress requirements
Idaho jurisdictions follow the International Residential Code (IRC), which requires every sleeping room to have an emergency escape and rescue opening — in a basement, that almost always means an egress window. The key numbers:
- Minimum openable area: 5.7 square feet (5.0 sq ft is allowed for openings at grade level)
- Minimum opening height: 24 inches
- Minimum opening width: 20 inches
- Maximum sill height: 44 inches above the finished floor
- The window must open from the inside without keys, tools, or special knowledge
Window well requirements
When the egress window sits below grade — which is nearly every East Idaho basement — it needs a window well that gives a person room to escape:
- Minimum well area: 9 square feet, with a minimum 36-inch projection from the foundation
- Wells deeper than 44 inches must have a permanently attached ladder or steps
- Well covers are allowed, but they must open easily from inside without tools
- Proper drainage in the well matters in our climate — a well that fills with snowmelt and refreezes is both a hazard and a moisture problem
What installation involves
Adding an egress window to an existing basement means saw-cutting the foundation wall, structurally framing the new opening, setting the window, excavating and installing the well, and handling drainage and waterproofing. It's very doable — we do it routinely as part of basement finishes — but it's foundation work, not a weekend window swap. In the Idaho Falls area, a professionally installed egress window with well typically runs $2,500 to $5,000 depending on soil, access, and the window you choose.
One more reason to do it right: a basement bedroom without legal egress can't be marketed as a bedroom when you sell, and more importantly, it's a life-safety issue for whoever sleeps there. Always confirm details with your local building department — requirements are enforced locally and can vary slightly by jurisdiction.
Common Questions
Do I need a permit to add an egress window in Idaho?
Yes. Cutting a foundation and adding an egress window is structural work that requires a permit and inspection in Idaho Falls, Pocatello, and surrounding jurisdictions. We pull permits and schedule inspections as part of the job.
Does every basement room need an egress window?
Every sleeping room needs its own egress opening, and basements with habitable space generally need at least one. A family room can often rely on one egress opening for the basement, but each bedroom needs its own.
Can an egress window be added to any foundation?
Almost always, yes — poured concrete and block foundations can both be cut and framed for egress. Site conditions like utility lines, grade, and interior obstructions determine placement. We evaluate this during a free on-site estimate.
Planning a project in East Idaho?
Carter Built Construction gives free, no-obligation estimates in Idaho Falls, Pocatello, Rexburg, and throughout the region.