building

Duplex Conversions

Converting a “single-family residence” to a “duplex” is a great investment opportunity. This pamphlet will give you a general idea of what property would qualify and what it takes to convert a “single-family residence” to a “duplex.” Topics discussed include lot requirements and some of the building code requirements.

Zoning Requirements:

  • 2 parking spaces for each dwelling behind front yard setback.

  • Duplexes are allowed only in the following zones:

    LDR 2

  • Minimum lot width is 60 feet.

  • Minimum lot depth is 60 feet

  • Minimum lot area is 10,000 sq.ft.

    LDR 3

  • Minimum lot width is 50 feet.

  • Minimum lot depth is 60 feet.

  • Minimum lot area is 8,000 sq.ft.

MDR1 & MDR2

  • Minimum Lot Width is 60 Feet

  • Minimum Lot Depth is 60 feet

  • Minimum Lot Area is 6,000 square feet

STRONGLY SUGGESTED: Prior to purchasing the property, schedule a walk-through with an inspector, because a building permit is required after the purchase of the household to convert the property to a duplex.

Building Requirements: 

  • Separate entrances for each dwelling unit needs to have a 36" x 6'8" door to the public way.

  • A 6'8” finishing height on the stairs is required.  Stairs are required to be lit.  Handrails are installed with 4 or more continuous stairs.  (Finishing height is from the nose of the step to the finished ceiling.)

  • All life safety features must be up-to-date.

  • Egress windows in sleeping rooms need to have 5.7 square feet of openable space.

  • Opening windows must have a maximum sill height of 44" above the floor level.

  • Entrance stairs from the outside are code-compliant.

  • The minimum hallway width is 36" and height is 6'8".

  • All livable space has a 7 ft. minimum ceiling height.

  • Building changes require that you apply for a building permit.

Electrical Requirements:

  • Separate meter is required for each dwelling unit.

  • A bathroom fan or window must be provided.

  • Outlets are GFCI-protected in the bathroom, kitchen countertop, and outside areas.

  • Electrical wiring is protected with covers installed; no cords for permanent wiring.

  • A licensed electrician (who is not the owner) is required to complete electrical work on a rental property.

Mechanical Requirements: 

  • Separate conditioned air ducting for each dwelling unit (separate furnace).  Units cannot share air.

  • Gas lines must not run through Building A to service Building B.  A licensed mechanical contractor is required to install gas lines.

  • A licensed mechanical contractor is required, that is not the owner, to do the work when working on a rental property.

Plumbing Requirements:

  • Separate shut-off of water supply for each dwelling unit is required. 

  •  A licensed plumber is required, that is not the owner, to do the work when working on a rental property.

Fire Requirements:

  • Fire separation between units.

  • Smoke detectors are installed and functional in halls and bedrooms to meet current code.

  • CO detectors are installed and functional in hallways.

  • In plain sight in the kitchen, a fire extinguisher (class 2A10BC minimum) is installed and functional.