Deck railing and stair basics in Minnesota and Wisconsin
By Jeff Rabkin, JustFix Wood · Published September 26, 2026
This is general guidance, not legal advice. Codes change, and cities in both states can add their own rules. Always check with your local building department before new work.
Minnesota
Minnesota's residential code is based on the International Residential Code (IRC). Under the IRC, a guard is required where a deck surface is more than 30 inches above the ground, and it's typically at least 36 inches tall. Openings are generally limited so a 4-inch sphere can't pass through.
Wisconsin
Wisconsin one- and two-family homes follow the state's Uniform Dwelling Code (UDC). It is its own code, not the IRC, and it generally requires guards on decks and stairs at a lower height above grade than the IRC does. Hudson and other St. Croix County communities may have local requirements too.
What this means for repairs
Older decks often have railings that were fine when built but are lower, or have wider gaps, than today's rules. When I repair a railing I'll point out anything that doesn't meet current requirements so you can decide what to do about it.
The most important thing isn't the number on a tape measure. It's whether the railing moves when you lean on it. A loose railing is a safety problem at any height.
Where to check
Minnesota: the Department of Labor and Industry (dli.mn.gov) and your city's building department. Wisconsin: the Department of Safety and Professional Services (dsps.wi.gov) and your city or village office.
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