What It Costs to Finish a Basement in Idaho Falls (2026 Guide)
By Carter Built Construction · Updated July 12, 2026
Most East Idaho homes have a full basement — which means most East Idaho homeowners are sitting on unfinished square footage that costs far less to build out than adding on. Here's what basement finishing actually costs in the Idaho Falls area, and where the money goes.
Typical basement finishing costs in East Idaho
For a standard unfinished basement, a basic finish — framing, electrical, drywall, paint, flooring, and trim — typically starts around $25,000 to $40,000 in the Idaho Falls area. Adding a bathroom, kitchenette, or custom features like a theater room pushes full projects to $50,000 or more.
On a per-square-foot basis, budget roughly $25 to $50 per square foot depending on finishes and how much plumbing and electrical work is involved. Because the foundation, roof, and structure already exist, that's typically half (or less) of what new above-grade construction costs per foot.
The line items that move the number most
Three things drive basement budgets in our area more than anything else:
- Bathrooms — new rough-in plumbing, ventilation, and waterproofing typically add $10,000–$20,000 depending on fixtures
- Egress windows — a legal basement bedroom requires a code-compliant egress window; cutting the foundation and installing a well typically runs $2,500–$5,000 per window
- Moisture management — insulation, vapor control, and addressing any existing seepage before covering walls; skipping this step is the most expensive mistake a basement project can make
Permits and code in Idaho Falls
Yes, finishing a basement requires a building permit in Idaho Falls and surrounding jurisdictions — especially when you're adding bedrooms, bathrooms, or moving electrical and plumbing. Bedrooms must have proper egress, and ceiling heights, smoke detectors, and stair details all get inspected. We handle permits and inspections as part of every basement project, so the finished space is legal, insurable, and counts toward your home's value when you sell.
Is finishing a basement worth it here?
In East Idaho's market, finished basement square footage is one of the cheapest ways to add livable space and resale value — you're building rooms inside a structure you already own. A basement bedroom and bathroom also make a big difference for appraisals and for buyers with larger families, which describes a lot of the local market.
Common Questions
How long does a basement finish take?
A typical basement remodel takes 6 to 12 weeks depending on scope. Simple finishes with basic framing and drywall are faster; projects with bathrooms, kitchenettes, or custom features take longer. We provide a clear timeline with every estimate.
Do I need an egress window to add a basement bedroom?
Yes. For a room to legally count as a bedroom in Idaho, it needs a code-compliant egress window — a large enough openable window with a maximum sill height and, below grade, a window well that meets size requirements. We install egress windows as part of our basement projects.
Can you match the finish quality of the upstairs?
Absolutely. Modern basement finishing — with proper insulation, lighting design, and the same trim, doors, and flooring quality used upstairs — should feel like the rest of the house, not like an afterthought.
Planning a project in East Idaho?
Carter Built Construction gives free, no-obligation estimates in Idaho Falls, Pocatello, Rexburg, and throughout the region.