Detached Residential Garages

This page provides basic information for one story light-wood-framed detached residential garage construction.  It does not address pole buildings, multi-story buildings, buildings with interior partitions, buildings with basements or buildings constructed for uses other than a private garage. Our Residential Garage packet, here, includes even more information and the forms needed to apply for residential garage permit. We encourage you to stop into the office in the planning phase of your garage project so we can look at GIS mapping of your property and talk about setback and other requirements.

No permit is required for buildings 200 sf or less, but building and zoning setback requirements do apply.

Use the forms in the Residential Garage Packet. All plans must be drawn to scaled in black or blue ink with the scale noted on the plans. Do not use pencil (it does not photocopy well). Clearly designate proposed work and existing conditions. Provide complete structural information. 

Draw to scale and indicate:

  • Legal description and north arrow.
  • Location and dimensions of all existing structures.
  • Dimensions of lot and survey monuments on which the site plan is based, for example,  found property corner pins placed according to a recorded survey or plat.
  • Distance from proposed garage to property lines, to dwelling and to other structures.
  • Driveway location.
  • Indicate whether you will use a frost footing or an engineered slab.
  • Where walls exceed 10 feet, analysis by an engineer is required with documentation submitted.

As a general rule, the following header sizes are acceptable:

  • For openings not exceeding 3’-6”, (2) - 2x4s on edge with one cripple stud each end.
  • For openings not exceeding 5’-0”, (2) - 2x6s on edge with one cripple stud each end.
  • For openings not exceeding 9’-0”, (2) - 2x12s on edge with two cripple studs each end.
  • For openings exceeding 9’-0”, an LVL header is required.  For information on LVL headers, contact an LVL supplier.

Must be available on site at framing inspection.

5 inch reinforced slab on grade with 60 inch drop footings, poured concrete or core-filled block or, for garages up to 1,500 sf, pre-engineered floating slab with thickened edges, reinforced as detailed.  Slabs for larger garages must be designed and plans certified by a Minnesota licensed structural engineer.

Setbacks are required distances from property lines and other buildings of the same or adjacent lot.  Construction must comply with the 2010 Duluth Unified Development Chapter (UDC), including overlay district requirements, and Minnesota State Residential Code (MSRC) requirements for location on lot.  The following is a summary of setback requirements.

Zoning Setback Requirements (UDC 50-14 and 50-21.3)
  • Rear property line: 5 feet from rear property line.                                                                                   
  • Front property line: As required for the dwelling.  Site specific.
  • Side property line: 3 feet.  Building code requirements are more restrictive.  See UDC for corner lots.
  • Adjoining Property: 10 feet from the principal structure on the adjoining property.
Building Code Location on Lot Requirements

Exterior Walls

  • Required distance from property lines:
    • 5 feet, except when exterior wall has a fire resistance rating of one-hour from both sides and no openings.
  • Required distance from dwelling units on the same lot:
    • Garages located less than 3 feet from a dwelling unit on the same lot shall be protected with not less than ½ inch gypsum board applied to the interior side of exterior walls that are within this area. Openings in these walls shall be regulated by Section R302.1. This provision does not apply to garage walls that are perpendicular to the adjacent dwelling unit wall.

Overhangs

  • Required distance from property lines:
    • 5 feet, except when exterior wall has a fire resistance rating of one-hour from both sides and no openings, then 2 feet.
  • Required distance from other buildings on the same lot:
    • 5 feet, except when eave has a fire-resistive rating of one-hour on the underside and no openings, then ≥ 2 to < 5 feet.

Maximum 20 feet from front grade to highest point of a flat roof or the average height of the highest gable.

May not exceed 1/3 of floor area and must be open to area below.  If greater than 1/3 of the area is used or the attic area is enclosed, it is considered a second story.  Garages with a second story need to conform to the Minnesota Residential Code and will be reviewed by a plans examiner. If the mezzanine is closed in and a second story is established, a Minnesota licensed structural engineer must design the foundation or the applicant may use Construction Services’ frost protected shallow foundation handout.

Any single accessory structure may not exceed 30% of the rear yard.  All accessory structures on a lot may not occupy more than 60% of the rear yard area.

Garage surface may be concrete, asphalt, sand, gravel, crushed rock, or natural earth.