Minnesota code timeline · Structural · 1990

Basement Egress Windows in Minnesota Homes Built Before 1990

A basement bedroom needs a window large enough to climb out of and for a firefighter to climb into. Finished basements that predate the requirement often have windows that do not meet it.

By Karl Espilseth, Founder, Tarn · Updated

What it is

An egress opening is a window or door sized so a person can get out under their own power and a firefighter in full gear can get in. The code sets a minimum clear opening area, minimum width and height, a maximum sill height above the floor, and — for a below-grade window — a window well big enough to actually stand and climb in. In Minnesota these requirements come through IRC R310 as adopted in MN Rule 1309.

Why it matters

A finished basement is one of the most common ways a home gains a bedroom count and listed square footage, and it is also where this requirement most often goes unmet. A basement sleeping room without a conforming opening predates the standard rather than breaking it — code changes apply going forward, not retroactively. But it is worth understanding for two practical reasons: it is a genuine life-safety consideration in the room where someone will be asleep, and appraisers and some insurers treat a room without conforming egress differently from a bedroom when they are counting what the home has.

What's worth doing next

Measure the actual clear opening rather than the window's nominal size — the number that matters is how much unobstructed space you get when it is fully open, which is smaller than the frame. If the home was finished below grade before 1990 and the listing counts a basement bedroom, ask whether an egress window was ever permitted. Retrofitting one means cutting the foundation wall and excavating a well, which is why it costs what it does.

I built Tarn as a homeowner, not a code official. Everything on this page is sourced to published Minnesota law and linked so you can check it yourself.

Minnesota uses a single statewide building code, so these requirements are state law rather than city ordinance — they apply the same way across every Minnesota city Tarn covers, except where noted. Code changes are also prospective: they apply to work done after the change, not retroactively to homes already standing. A home that predates a standard isn't out of compliance with anything. It just predates it, and that's worth knowing before you buy.

Check this against a specific address

Tarn runs the full Minnesota code timeline automatically when you search an address with a year built in any of these cities.

Search an address

Other Minnesota code-era factors

See the full Minnesota code timeline