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 current Oregon Residential Specialty Code. 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. These standards are listed in Brochure #9, Converting 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 http://www.portlandmaps.com/ 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.
Find out how to research your property and where to locate the information in preparation for your permit application
Things to consider
(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.
The Bureau of Development Services allows special standards for existing situations:
- Ceiling height
- Emergency Egress Windows
- Insulation and Ventilation
For a complete overview of habitable space standards for converted areas, see our Converting Attics, Basements and Garages to Living Space brochure.
(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. A garage that was not constructed with a permit because it was previously exempt due to its use and size will need to have all structural elements submitted and reviewed as part of the conversion to living space.
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) Additional Sinks and Kitchens
If your project will add a sink, such as a bar sink in an entertainment area, you may need a “Covenant for a Sink Outside of the Primary Kitchen, Bathroom or Laundry Room inside a Single-Family Dwelling”. 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 at (503) 823-7526 for additional information. If required, this document must be recorded with Multnomah County before your permit can be issued.
If your final project will include both a kitchen and a bathroom that can be used independently of the remainder of the dwelling, it may need to be permitted as an Additional Dwelling Unit. The covenant may not be sufficient for this configuration because of Building Code requirements which define a “Dwelling Unit” as “a single unit providing complete independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking and sanitation.” We recommend that you visit the Development Services Center to discuss your project during the design stage.
(5) Engineering Calculations
When the scope of work will change the structural load in the structure, 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.
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 all conversion standards noted in the brochure, Converting Attics, Basements and Garages to Living Space 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 listed, 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.
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.