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Development Services

From Concept to Construction

Phone: 503-823-7300

TTY : 503-823-6868

1900 SW 4th Ave, Portland, OR 97201

Manufactured Homes

Information related to manufactured homes: putting one in a new location or altering an existing home.

Applying For My Permit

The following information must be submitted when applying for a permit to install a manufactured dwelling. Since every project is unique, there may be some situations where you will be asked to provide additional information.

Site Plan (Scale site plans to minimum scale of 1”=10’ and at least 11” x 17” in size)
  • Lot and building setback dimensions.
    • The “lot” for a manufactured dwelling on an individual lot (MI) is the property line
    • The lot for a manufactured dwelling installed in a park (MT) would be the lot within the park where the home is located.
  • Property corner elevations (if there is more than a four foot elevation differential, the site plan must also show existing and proposed contour lines at two foot intervals. A separate grading plan may be required to legibly show grading changes.)
  • Location and dimensions of easements and driveways
  • Footprint of structure (including decks and dimensions of eaves)
  • Location of wells/septic systems
  • Lot area
  • Location of all cuts and fills on the lot
  • Building coverage area and percentage of coverage
  • North arrow
  • Impervious area (structures, paving, etc.)
  • Existing structures on site
  • Location of utilities (storm & sanitary sewers, water, gas, etc. including size of service and street location)
  • Surface drainage
  • Width of adjacent right-of-way and curb height
  • Landscape plans
  • For a manufactured dwelling installed in a park, a plan of the park detailing the separate lots with the lot identified where the specific manufactured dwelling will be installed
  • A manufactured dwelling that is installed within a floodplain must meet elevation requirements
Include the Floor Plan from Manufacturer
 
Building Elevations drawn to scale and showing:
  • All four views (left, right, front and rear) of manufactured home, including foundation
  • Finished grade for specific site
  • Exterior siding material
  • Roof pitch (3/12 minimum) and eave overhang (12” minimum)
  • The City also requires that sections show that the home is a maximum 12” above grade at the lowest point, has conventional residential siding and at least 12” eaves
Foundation Plan (drawn to ¼” =1’ scale )
  • Concrete runners, slab and pads
  • Spacing for supports (piers, blocks, etc)
  • Size of all components
  • Section detail
  • Pier locations either per OMDS or manufacturer’s specifications
  • 18 x 24 crawl access
  • Ventilation
  • Skirting or perimeter walls. Perimeter walls up to four feet high, measured from the bottom of the footing to the top of the wall, structural CMU, grouted solid or solid concrete, or pressure treated wood pony walls shimmed 16” center to center are acceptable ( 304n, OMDS).The OMDS states that all perimeter walls must be engineered.
  • Poly will be laid in the crawl space and subsurface disposal will be required at the direction of the inspector
  • Tie down locations with manufacturer’s listing information or structural engineer stamp for single-wide homes
Note: Daylight basements require plans and calculations stamped by an Oregon Registered Structural Engineer.
 
Perimeter Wall Section Detail (Skirting)
  • Framing details
  • Footing details
  • Attachment details
To submit for a MP permit, bring the completed building permit application and four (4) copies of site, floor, elevation, foundation, perimeter wall section, related materials and intake fees to the Development Services Center.

To submit for an MI permit, contact the Permitting Services staff at (503) 823-4172 to schedule a new single family residential (NSFR) intake appointment.

Information on the addition of an accessory building.

Information on the addition of a deck.

If you are hiring sub-contractors to do work on your project, and know who they are when applying, they will be listed on your permit at that time. If you don't know when you apply for your permit, they can be added after issuance. Sub-contractors you hire must be registered with the State of Oregon and carry a current CCB license.
 
THINGS TO CONSIDER:
(1) Appliances
Appliances such as electric ranges and clothes dryers must be specifically listed for use in manufactured dwellings. Solid fuel burning appliances, such as fireplaces, wood stoves and pellet stoves must be specifically listed for use in manufactured dwellings.

Gas and oil fuel-burning appliances, such as furnaces and water heaters, do not need to be specifically listed for use in manufactured dwellings. These appliances can be installed as per their listing.
 
(2) Ramadas
A Ramada is a structure built over the home but not attached to the home. It must be a minimum of 18 inches above the top of, and six inches beyond the sides of, a manufactured dwelling. A ramada is reviewed and permitted like a pole structure, and requires an engineered design.
 
(3) Alterations
Alterations to manufactured dwellings require a permit and plans. The State issues the permit if the alteration is before the time of sale to the first consumer. The City issues the permit if it is a “secondary alteration” after the initial sale to the first consumer. Any alteration or addition that adds vertical weight or lateral loads to a manufactured dwelling requires engineering, including adding interior masonry around a wood stove or cutting a header.
 
(4) Site Modifications
  • All site modifications such as driveways, daylight basements, ramadas, cabanas, carports, garages, additions, porches, decks, etc. must be shown.
  • Except for porches and decks, any accessory structure must be permitted separately.
  • A home that has a roof overbuild must be shown as adequate to support such overbuilding. A home that has trusses designed to support 30 psf snow load will be assumed capable of supporting a simple garage gable extension.
(5) Decommissioning a Septic Tank or Cesspool
When installing a manufactured dwelling on an individual lot, the septic tank/cesspool must be located if it exists.
  • Visit the records staff at the Development Services Center to locate any old plumbing records showing a septic system/cesspool
  • If the septic system/cesspool is decommissioned, and within ten feet of the new structure, you must sign a disclaimer for on-site-sewage disposal system form
  • If the septic system/cesspool is within ten feet of the new structure, it will need to be decommissioned
Call Environmental Soils staff at (503) 823-6892 for more information on decommissioning septic tanks and cesspools.