Basement Bedroom Requirements in Minnesota — and How to Finish One Right

A basement bedroom is the cheapest legal bedroom most Twin Cities homeowners can add. It is also the one most often done wrong.

The requirements

Item	Requirement
Egress opening	5.7 sq ft net clear (5.0 at grade), 24 in min height, 20 in min width, sill ≤ 44 in above floor, opens without a key or tool
Window well	Min 36 in projection, 9 sq ft area; permanent ladder or steps if deeper than 44 in
Ceiling height	7 ft over the required floor area
Floor area	70 sq ft min, no dimension under 7 ft
Heat	Permanent source holding 68°F
Alarms	Interconnected smoke alarm in the room, CO alarm within 10 ft
Insulation	Basement wall assembly per Minnesota energy code, with a continuous rigid or spray foam layer against the foundation
Egress path	Route out that does not pass through a mechanical room

Moisture comes before framing

This is the part people skip. If the basement takes water — even occasionally — fix that first:

• Extend downspouts 6+ feet from the foundation
• Regrade so soil falls away from the house
• Clean and repair gutters
• Repair or add drain tile and a sump if the water table demands it

Framing and insulating over an active moisture problem builds a mold farm inside a wall you just paid for. We will not do it, and no honest contractor should.

The insulation detail that matters in Minnesota

A concrete foundation wall is cold and it moves vapor. The assembly that works here is a continuous layer of rigid foam or closed-cell spray foam directly against the concrete, then a framed wall inboard of it, with no polyethylene vapor barrier trapping moisture between two impermeable layers. Get this wrong and the wall sweats.

Cost and timeline

Scope	Range	Timeline
Bedroom only, egress already in place	$9,000 – $18,000	3 – 4 weeks
Bedroom plus new egress window	$14,000 – $28,000	4 – 6 weeks
Bedroom plus 3/4 bath	$28,000 – $50,000	6 – 10 weeks

The return

Below-grade space is appraised differently than above-grade, so do not expect a basement bedroom to add the same value as a main-floor one. What it reliably does is add rentable space. A permitted basement bedroom in Minneapolis or St. Paul commonly rents in the several-hundred-a-month range on its own, which puts payback on a $20,000 project inside three years — and it is a room you can point to on the listing when you sell.

Get it inspected

Every item above is verifiable by a city inspector in one visit. That inspection is what turns a finished room into a bedroom that counts. We pull permits on every basement bedroom we build.