The rule in one sentence
Every sleeping room in a basement needs its own emergency escape and rescue opening — and a standard basement window almost never qualifies.
This single requirement decides whether a basement bedroom is legal, and it is the largest cost swing on most Pocatello basement projects. It exists for two reasons: so someone can get out, and so a firefighter in full gear can get in.
The dimensions
| Requirement | Minimum |
|---|---|
| Net clear opening area | 5.7 sq ft |
| Net clear opening height | 24" |
| Net clear opening width | 20" |
| Maximum sill height above finished floor | 44" |
The trap in this table: the minimum height and minimum width cannot both be used at once. A 24" by 20" opening yields 3.3 square feet — barely more than half of what's required. The dimensional minimums are floors, not a recipe. To reach 5.7 square feet you need substantially more than the minimum in at least one direction.
"Net clear" also means what it says: the actual unobstructed hole when the window is fully open, measured through the opening. Not the rough opening in the wall. Not the glass area. On a casement, the sash swings clear and the numbers work out favourably. On a slider, half the width is gone permanently, which is why most existing basement sliders fail.
Window wells
Because a basement egress window sits below grade, a window well is almost always required.
| Requirement | Minimum |
|---|---|
| Horizontal area | 9 sq ft |
| Width | 36" |
| Projection from wall | 36" |
The well must allow the window to open fully — a well that physically blocks the sash defeats the purpose and fails inspection.
A window well deeper than 44 inches must have a permanently affixed ladder or steps. Not a portable ladder stored nearby — permanently affixed. The ladder is permitted to encroach a maximum of 6 inches into the required well dimensions, so a well sized exactly to the 9 square foot minimum still works with a ladder installed. Deep wells are common on Pocatello homes with full-depth basements, and this requirement gets overlooked constantly.
Why this is the big cost item
If your basement has compliant egress already, this page costs you nothing. If it doesn't, adding one means:
- Cutting a foundation wall. Concrete cutting on a poured or block wall, sized for the window plus framing.
- A structural header. You've removed part of a load-bearing wall. Guidance from other Idaho jurisdictions notes a header is required at the top of a new opening, with doubled dimensional lumber typical depending on span.
- Preservative-treated lumber anywhere framing contacts the concrete opening.
- Excavation outside for the well, to depth.
- Drainage. A window well is a hole against your foundation that collects water and snow. In Pocatello, that means it fills with snowmelt every spring unless it drains properly. This is not optional detailing.
- The window and well themselves, plus backfill, grading and finish.
Multiply by the number of bedrooms. Two bedrooms means two openings — there is no shared-egress provision for sleeping rooms.
Pocatello-specific considerations
Snowmelt and drainage
A window well is a basin cut into the ground next to your foundation. Through a Pocatello winter it collects snow, and through the spring thaw it collects meltwater. Without a proper drain connected to the foundation drainage system or daylighted, that water sits against the foundation and finds its way in — into the very bedroom you just finished. Ask specifically how the well will drain, and consider a well cover.
Backfill and grading
Excavation for a window well disturbs the backfill against your foundation. How that soil is recompacted and graded afterward affects drainage for years. Grade should slope away from the house, not toward the new well.
Egress path
The opening must discharge to a yard, court or public way. A well that opens into a fenced side yard with no gate, or under a deck, can create problems. Check what's above and around the proposed location before you commit to it.
Common questions
Does a den or office need egress?
The code requires an escape opening for basements and every sleeping room. Beyond the sleeping-room requirement, whether a given habitable room needs one depends on the specific configuration and how the space is classified — worth confirming with the building department for your layout. The safe planning assumption is that any room you might ever call a bedroom needs it.
Can I call it a bedroom without egress?
No. Not legally, not on an appraisal, and not on a listing. This causes real problems at resale when an inspector or appraiser counts bedrooms and gets a different number than the listing claims.
My basement already has a window. Does it count?
Measure the net clear opening with the window fully open, and measure the sill height from the finished floor. Most existing basement windows in older Pocatello homes fail on area, sill height, or both. Sliders in particular rarely pass because half the width never opens.
Is this DIY-able?
Cutting a structural opening in a foundation wall is one of the few basement tasks where the answer is clearly no for most homeowners. It's structural, it needs a properly sized header, it requires exterior excavation, and the drainage detailing determines whether your new bedroom floods. It's also inspected specifically.
What about an egress door instead?
A walkout or a bulkhead door can satisfy the requirement, and on a sloped lot a walkout is often the better answer — it's more usable and adds more value than a window well. It's a bigger excavation and a bigger project, but worth pricing if your grade allows.