Duluth Chimney Guide: Repairs, Licensing, Permits (2026)

Updated October 19, 2026. This guide is general information, not legal or engineering advice. Rules change, so confirm with the agency listed before you start work.

Quick reference

Topic	What to know	Source
Older homes	About 44% of Duluth housing built before 1940	City of Duluth housing market analysis
Climate	About 90 in. of snow a year; about 100 days with highs at or below 32°F	Duluth climate data (Wikipedia)
Inspection	At least once a year	NFPA 211, via CSIA
Sweeping	Masonry fireplace at about 1/8 in. of soot, sooner with glazed creosote	CSIA
MN license	Needed for more than one special skill; single-skill (e.g. masonry only) and under-$15,000 exemptions	MN Dept. of Labor and Industry
Recovery fund	Licensed contractors only; up to $75,000 per claim	MN Dept. of Labor and Industry
Duluth permits	Construction Services and Inspections division	City of Duluth
Wisconsin	Dwelling Contractor credentials to pull a 1–2 family permit	Wisconsin DSPS

Why does Duluth's climate wear out chimneys?

Duluth averages about 90 inches of snow a year and around 100 days when the high stays at or below freezing. The first freeze usually comes around September 30 and the last around May 14, and lake-effect snow can drop a foot or more on the city while inland areas get much less. Masonry that stays wet through that many freezing days loses mortar, cracks at the crown and spalls at the brick face. Add a housing stock where the City estimates roughly 44 percent of homes were built before 1940, and chimney repair is a routine part of owning a house here.

What mortar should be used on old brick?

The National Park Service's Preservation Brief on repointing says new mortar should be softer and more vapor-permeable than the masonry units. Straight portland cement mortar resists the movement of water, trapping moisture in the wall, and because it's stronger than soft brick, stress is relieved through the brick instead, causing cracking and spalling. The same brief says leaks from roofs, gutters and other sources should be fixed before repointing, or the work won't last.

How often should a chimney be inspected and swept?

NFPA 211, quoted by the Chimney Safety Institute of America, says chimneys, fireplaces and vents should be inspected at least once a year for soundness, freedom from deposits and correct clearances, with cleaning, maintenance and repairs done if needed. CSIA recommends sweeping a masonry fireplace when soot reaches about one-eighth of an inch, sooner if glazed creosote is present, and sweeping factory-built fireplaces when any noticeable buildup appears. Even chimneys that see little use should be checked for nests and deterioration.

Who needs a license to work on a Minnesota chimney?

The Minnesota Department of Labor and Industry requires a residential building contractor or remodeler license for anyone who contracts directly with a homeowner for work in more than one special skill. Masonry and concrete, which includes masonry fireplaces, is one of those special skills, and a specialty contractor who provides only one special skill isn't required to hold the license. Contractors with gross annual receipts under $15,000 who hold a Certificate of Exemption are also exempt. A company that rebuilds a chimney and also does roofing, carpentry or other trades on the same job generally needs the license.

DLI points out that only homeowners who hire a licensed contractor can use the Contractor Recovery Fund, which covers direct out-of-pocket losses up to $75,000 per claim after a court judgment. You can look up a license on DLI's license and registration lookup. DLI also warns that a number beginning with "IR" is not a license.

What should be in the contract?

DLI's consumer guidance recommends getting everything in writing: the specific materials, start and completion dates, a payment schedule, who pulls permits, and written change orders. It lists red flags including demands for full or substantial payment before work begins and refusing to provide a written contract or license number. For larger jobs, ask for lien waivers from subcontractors and suppliers before final payment.

Who issues permits?

In Duluth, the City's Construction Services and Inspections division handles building, mechanical and related permits, and its list of permit types includes fireplaces. Ask your contractor whether a rebuild, relining or new appliance needs a permit and who will pull it. Outside the city, check with your city or township.

What's different in Superior, Wisconsin?

Wisconsin's Department of Safety and Professional Services requires anyone applying for a building permit on a one- or two-family dwelling to hold a Dwelling Contractor certification, or hold or employ a Dwelling Contractor Qualifier, unless the applicant is the owner who lives in the home. Minnesota's license doesn't carry over. Check with the City of Superior on local permits.

Questions to ask a chimney company

Do you hold a Minnesota DLI license, or which exemption applies to you?
Is your sweep CSIA-certified, and will I get a written report with photos?
What mortar will you use on my brick, and why?
Does this job need a permit, and will you pull it?
What's warrantied, and for how long?

Common questions

Do chimney contractors need a license in Minnesota?

Contractors selling homeowners work in more than one special skill need a DLI residential contractor license. A masonry-only specialist can be exempt, as can contractors under $15,000 a year with a Certificate of Exemption.

How often should a chimney be inspected?

At least once a year, according to NFPA 211, the standard the Chimney Safety Institute of America references.

Who handles building permits in Duluth?

The City of Duluth's Construction Services and Inspections division.

Duluth chimney guide (2026)