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Development Services

From Concept to Construction

Phone: 503-823-7300


1900 SW 4th Ave, Portland, OR 97201

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Conversion to Living Space

Information on converting your attic, basement or garage into additional living space.

Getting Started

A building permit is required to convert attics, basements or garages to living space. Depending on the scope of work, your project may also require electrical, plumbing or mechanical permits. 

The Bureau of Development Services sells a "Residential Combination" permit package. This allows you to call for all inspections using just the Building Permit (RS) IVR number and pay for all the permits at one time. You will need to submit the trade (mechanical, electrical, and/or plumbing) application(s) signed either by you, if you are doing these portions of the work yourself, or by your licensed subcontractors. If you do not have your completed subcontractor forms when you are applying for your residential permit (RS) you will have to apply for trade permits separately from the building permit. Sub-contractors that you hire must be registered with the State of Oregon and carry the correct licenses in association with their trade. 

Your permit will be reviewed under provisions in the Residential Specialty Code (formerly the One and Two Family Dwelling Specialty Code) based on the 2003 IRC. View more information on building codes. 

In general, when changing the use of a space, such as converting unfinished storage or utility areas to finished living space, the building code requires that the remodeled area conform to current code. The Bureau of Development Services has established alternative standards specifically for conversion projects. [Coverting Attics, Basements and Garages to Living Space] 

How to Check your House’s History

Depending on the age of your house, we may have inspection cards or microfilmed plans that will show the history of permit activity for your house. It is important to verify that the “existing” finished attic or basement was permitted as such in the permit records, and not just through the county assessor’s office. Information found on is reported from the county's assessor's office, and may not match the building permit history. There is no ”grandfathering-in” of these spaces, and to be considered living space, they would need to be legalized through the permit process.

Things to consider

The Bureau of Development Services has set up the following special standards for existing situations:

Applying For My Permit

The following information must be submitted when applying for a permit to convert a garage, attic or basement of an existing one or two family dwelling to living space. Since every project is unique, there may be some situations where you will be asked to provide additional information.

It is recommended to visit or call the Planning and Zoning staff (503) 823-7526 and Buildings staff (503) 823-7310 at the Development Services Center early in the planning of your project.

Complete building permit application form.

Site Plan (Scale site plans to most appropriate scale, e.g. 1”=10’ or 1/4”=1’)

  • Property lines, with dimensions
  • Adjacent streets and any easements
  • Property address and R number
  • North arrow
  • Distance between buildings and between buildings and property lines
  • Area (in square feet) of any existing or proposed buildings
  • Dimensions and area (in square feet) of any proposed paving. (If your project will add more than 500 square feet of impervious area you will need to provide a mitigation form and/or a stormwater plan)

Architectural Plans (Scale of plans to be ¼”=1’ and details scaled to ½”=1’. Single line drawings are not acceptable – plans must be drawn to show wall thickness)

  • Fully dimensioned floor plans (including locations) for each floor affected
  • Use of each room
  • Building sections showing typical wall, floor, ceiling, roof and foundation
  • Section with ceiling height for area of conversion
  • Stair details with dimensions for risers, treads and handrails
  • Insulation R value for ceiling, walls and floors
  • Plumbing fixture layout
  • Gas/oil furnace and water heater location
  • Electrical light fixtures, smoke detectors and fans

Structural Plans (Scale of plans to be ¼”=1’, details to be ½”=1’)

  • Floor framing for each floor, including lumber size, spacing and span, for attic conversions
  • Roof and floor framing plans may be required if walls, beams or other structural supports are removed or moved
  • Any engineering calculations may be attached to the plans but engineering details are to be incorporated into the plans or cross-referenced on the plans

To submit for a permit, bring the completed building permit application and four (4) copies of site, architectural and structural plans (for the area of proposed work and areas affected by such work) along with intake fees to the Development Services Center.

(1) Evaluating Existing Space
In unfinished areas, existing features such as ceiling heights, windows, stairs and insulation may not meet current building code requirements for finished space. These conditions could make it expensive, difficult or even impossible for you to change your attic, basement or garage into living space.

(2) Garage Conversions
You will need to show how you will provide the required parking space since parking in your driveway alone may not meet this requirement.

If your garage is detached and you want to convert it to living space, it may not meet setback requirements since the zoning code may not allow living space to be placed in the setback areas, even if it allows the garage to be in that location.

A detached garage may have structural deficiencies that would need to be upgraded in order to meet building code standards.

If your project requires construction in the public right-of-way, then the Portland Department of Transportation will review the project, and issue a separate transportation permit for this work as well. For more information about right-of-way requirements, contact the Portland Department of Transportation at (503) 823-7002.

3) Attic & Dormer Additions
If converting attic space to living space would mean raising the roof, the zoning code height regulations may affect your project. See information on Dormer Additions.

(4) Second Sink Covenant
If your project will add a kitchen, such as a bar kitchen in an entertainment area, you may need a Second Kitchen Covenant. This document is a statement of understanding that the addition of this facility does not create another dwelling unit, and that the structure is still a single-family dwelling. If you are unsure if your project will trigger this requirement, please contact Planning and Zoning staff for additional information. If required, this document must be recorded with Multnomah County before your permit can be issued.

(5) Engineering Calculations
When the scope of work will change the structural load in the house, it is important that you submit engineering calculations that show the continuity of the load path from floors or other affected members all the way to the foundation of the house.

You must determine if the existing attic floor structure is strong enough to carry the additional weight of people and furniture. It is very common that when tracing floor loads from the converted attic, it is the beam in the basement that will be overstressed. Situations like this are required to be resolved as part of the permit application.

(6) Adding a Bathroom to an Unfinished Basement
If you are adding a bathroom in the basement but intend to leave the remainder of the basement unfinished, the entire basement does not have to comply with these conversion standards. However, the ceiling height in the bathroom must comply. In addition, the stair to the basement and a three foot wide path through the basement from the stair must meet the headroom and other dimensional requirements noted in the conversion brochure. The other requirements listed (including exterior wall insulation, storm windows and egress windows) are not required if no other habitable space is proposed in the basement.

(7) Floodplains
If your house is located in a floodplain, there are restrictions that may limit your ability to add or to significantly improve your house without retrofitting it to be flood resistant. Please contact Site Development staff at (503) 823-6892 to discuss your project.

Plan Review Process

After you pay intake fees, your project will be "under review". The bureaus/review groups that will check a typical conversion project include:

  • Planning and Zoning Review
  • Life Safety Review
  • Structural Review
  • Site Development Review
  • Urban Forestry Review

Overview of the permitting process.

A checksheet is sent to the applicant when a reviewer needs additional information or a correction has to be made to the plans. When you have gathered the additional information or made the corrections, bring the plans/information to the Development Services Center. Reviewers will be notified that a checksheet response has been received, and review will continue.

More information on Checksheets.

Status Reports
Status reports are available after your project has been assigned to reviewers. Status reports show all reviews and include the reviewer’s name and phone number. To obtain a status report, call (503) 823-7000 and select option four (4) to have a status report faxed to you or call (503) 823-7357 to have one mailed to you.

Permit Issued
When the last technical review is approved, your permit will pre issued. You will be contacted when your permit is ready, and of your final fee total. Fees may be paid by cash, check, Visa or Mastercard.

If your permit is ready for issuance, you may pick up your permit between 8:00 am - 3:00 pm, Monday-Friday at Permitting Services, located on the 2nd floor of 1900 SW 4th Avenue, Portland, OR. For more information call (503) 823-7357.


The yellow inspection card lists all the inspections you will likely need during your construction project, and what work needs to be done first.

Once your building permit is issued, erosion control measures must be installed, prior to beginning any ground disturbing activities.

Applications & Handouts