Basement egress windows in Des Moines
Finishing a basement bedroom in Des Moines means an emergency exit, and in most houses that means cutting a bigger opening in the foundation and digging a window well. It is a structural job with a permit, not a simple window swap.
The size rules
Egress windows generally need a net clear opening of at least 5.7 square feet (5 square feet for an opening below ground), at least 24 inches of clear height and 20 inches of clear width, and a sill no more than 44 inches above the floor. Those minimums apply to the clear opening when the window is fully open, not the size of the frame, so a casement or a large slider is usually needed to meet them.
Permits
Cutting a new or larger opening, such as a basement egress window, changes the rough opening, so it falls outside that exemption and needs a permit. The City of Des Moines' permit exemption policy (effective July 1, 2023) lets window replacement skip a building permit only when the rough opening keeps its size and the finished egress opening is not reduced. The window also must not be one the code requires for smoke control, fire separation distance or safety glazing. The suburbs run their own building departments. West Des Moines, Ankeny, Urbandale and the other suburbs run their own building departments. Ask the installer who pulls the permit and check with the city before work starts.
What it costs
| Job | Published range | Source |
|---|---|---|
| Basement egress window, prefab | $2,500 to $5,000 | This Old House, Oct 2026 |
| Egress excavation and window well | $3,000 to $7,000 | This Old House, Oct 2026 |
The window is the smaller part of the bill. The foundation cut and the excavation drive the price. Then add the well and its drainage, and the yard repair afterward.
Questions to ask
- Who pulls the permit, and is the cost in the quote?
- How will the foundation be cut, and is a header needed above the new opening?
- What is at the bottom of the well: gravel to a drain, a tie-in to the drain tile, or nothing?
- Is a well cover or ladder included if the well is deep?
- Who calls Iowa One Call to locate buried lines before digging?
Questions Des Moines homeowners ask
Do I need an egress window in my basement?
A basement bedroom needs an emergency escape opening. An unfinished basement or a family room may not, but rules depend on what you are building. Ask the city building department or the contractor before you frame walls.
Can an egress window go in during winter?
Yes, but frozen ground makes excavation harder and can add cost. Many Des Moines homeowners schedule egress work from spring to fall.