The same code as any house
Minnesota Rules, part 1309.0010 makes the 2018 International Residential Code, with Minnesota amendments, part of the State Building Code. Under Minnesota Statutes, section 326B.121, the State Building Code applies statewide and supersedes the building code of any municipality.
Cutting openings, insulating and finishing a container turns it into part of a building. The building official reviews the result like any other house: foundation, structure, insulation, fire safety, exits, plumbing, electrical work and heating. Ask early what drawings and engineering the permit will need, because cutting the walls for windows and doors changes how a container carries its load.
Under Minnesota Rules, part 1300.0220, subpart 1, no one may live in the home until the building official issues a certificate of occupancy.
Zoning comes first
Before any building plan, the zoning ordinance for your address decides whether a home can go on the lot, where it can sit and how large it must be. Setbacks, minimum home sizes, design standards and the rules for accessory dwellings are set by each city, and by the county or township outside city limits.
Rochester shows why the order matters. Its Unified Development Code says "No storage container may be used for temporary or permanent human occupancy," and that storage containers may not be used as accessory dwelling units. The same code defines a storage container as a structure that is not part of a primary building and is intended for storage. Before you buy, ask Rochester Community Development (507-328-2600) how a home built from containers would be classified.
Deed covenants and homeowners association rules can also limit materials and design. Read both for the lot before you commit to a plan.
Ceiling height and bedroom windows
Minnesota Rules, part 1309.0305 requires at least 7 feet of ceiling height in habitable space, hallways, bathrooms, toilet rooms and laundry rooms, measured from the finished floor to the lowest projection from the ceiling.
A standard container has about 7 feet 10 inches of interior height. That leaves about 10 inches for ceiling insulation, the ceiling finish and any layers added to the floor. A 40ft high cube has about 8 feet 10 inches inside, which leaves about 22 inches.
Part 1309.0310 requires every sleeping room to have at least one operable emergency escape and rescue opening that opens to a public way or to a yard or court that opens to one. In a container home, each bedroom therefore needs an opening cut into the steel wall, such as an egress window.
Foundations and frost
Minnesota Rules, part 1303.1600 sets the minimum footing depth for frost protection: five feet in 34 northern counties, including St. Louis, Itasca, Beltrami, Clay and Otter Tail, and three and a half feet in the rest of the state, including Hennepin, Ramsey and Olmsted. Those depths apply unless an engineer competent in soil mechanics determines otherwise.
A shipping container is built to rest on its corner castings, so the foundation design starts from where each container bears. An engineer can design piers or a perimeter foundation that meets the frost depth and lines up with those points.
The soil matters too. MnDOT's statewide landscape study describes poorly drained and organic soils around Lino Lakes and Forest Lake and along the Vermillion River northeast of Farmington. It also describes lake sediments across the Red River Valley that hold poorly drained soils. A soil report tells the engineer what the ground under your lot will carry.
Snow on the roof
Minnesota Rules, part 1303.1700 sets the ground snow load used to design buildings at 60 pounds per square foot in 29 northern counties and 50 pounds per square foot in all others. The roof of a container home, whether it is the container roof or a roof built over it, is designed from that number. A pitched roof over the containers also sheds snow and leaves space for ceiling insulation.
Insulation and the energy code
Minnesota's residential energy code, Minnesota Rules, chapter 1322, sets the minimum insulation for a home. Its Table R402.1.1, as amended in part 1322.0402, calls for R-49 in the ceiling in both of Minnesota's climate zones, a wood-frame wall of R-20 (or R-13 plus R-5 continuous) in zone 6 and R-21 in zone 7, and R-30 in the floor in zone 6 and R-38 in zone 7.
Reaching those numbers inside a container uses up interior width and height, while insulation outside the steel keeps both. The Minnesota insulation guide compares the methods and explains why air sealing matters on steel.
Water, septic and power
A new well must be drilled by a licensed well contractor. Under Minnesota Statutes, section 103I.205, subdivision 4, a person may not drill, construct, repair or seal a well without a well contractor's license, apart from narrow exceptions. The Minnesota Department of Health's Well Management Section answers questions at 651-201-4600.
On a lot without city sewer, the home needs a septic system, which state law calls a subsurface sewage treatment system. Minnesota Statutes, section 115.55 requires counties to adopt septic ordinances that apply everywhere outside the cities and towns that have their own, and requires an inspection of every new system. Ask the county which septic ordinance covers your lot.
Every new electrical installation must be inspected, by the state or by a local government that runs its own electrical inspection, under Minnesota Statutes, section 326B.36.
Homes built in a factory
Some container homes are finished in a factory and delivered as modules. Minnesota Rules, part 1361.0200 defines an industrialized/modular building as one of closed construction, made or assembled off the building site, whose concealed parts cannot be inspected on site without disassembly, damage or destruction.
Under part 1361.0400, industrialized/modular buildings sold, offered for sale or installed in Minnesota must bear an Industrialized Buildings Commission seal and data plate. If a builder finishes your container home in a factory, ask whether its modules carry that seal, and ask your building official how the work on site will be inspected.
Getting the containers to the site
Container One arranges every delivery. Its published requirements are 110 feet of straight, unobstructed space for a 20ft container and 130 feet for a 40ft, at least 15 feet of height to drive, 22 feet of height along the entire unloading path and 10 feet of width. Check a wooded lot or a narrow drive against those clearances before the foundation goes in.
Placing a container onto a raised foundation takes a lift, such as a crane, so plan that step with your builder.
Container One publishes no fixed delivery window. Timing depends on your location, when payment is received, the weather and other factors, and its Delivery/Dispatch department contacts you to schedule a date and time.
Rural sites add road questions. MnDOT posts spring load restrictions on state highways with at least three days' notice, and refers drivers to the county for county road limits. A township or county may also designate a road used only occasionally as a minimum-maintenance road under Minnesota Statutes, section 160.095. Mention either one in your quote request.
Questions to settle before you buy containers
- Does the zoning for this lot allow the home you plan, and what setbacks, minimum size and design standards apply?
- How will the building official review a home built from containers, and what drawings and engineering does the permit need?
- Which climate zone, frost depth and snow load apply in this county?
- Where will water, septic and power come from, and which office permits each one?
- Will the home be built on site or in a factory, and does a factory builder's work carry the required seal?
- Can a truck reach the site with the clearances above, and how will the containers be set on the foundation?
The Minnesota permit guide covers the rules for storage containers in Minneapolis, St. Paul and Rochester. The 40ft high cube page lists the dimensions of the tallest standard container.
Sources
- Minnesota Statutes, section 326B.121, State Building Code
- Minnesota Rules, part 1309.0010, Adoption of the International Residential Code, part 1309.0305, Ceiling height and part 1309.0310, Emergency escape and rescue openings
- Minnesota Rules, part 1300.0220, Certificate of occupancy
- Minnesota Rules, part 1303.1600, Footing depth for frost protection and part 1303.1700, Ground snow load
- Minnesota Rules, chapter 1322, Residential Energy Code and part 1322.0402, Building thermal envelope
- Minnesota Rules, part 1361.0200, Definitions and part 1361.0400, Certification
- Minnesota Statutes, section 103I.205, Well construction and the Minnesota Department of Health, Wells and Borings
- Minnesota Statutes, section 115.55, Subsurface sewage treatment systems and section 326B.36, Electrical inspections
- City of Rochester, Unified Development Code
- MnDOT Mn/Model, St. Croix Moraines and Outwash Plains and Red River Prairie
- MnDOT, Seasonal Load Limits and Minnesota Statutes, section 160.095
- Container One, Shipping Container FAQs
This guide is general information about public rules, not legal, engineering or design advice. The building official for your parcel decides what your project needs.