A building permit is required for any addition to a single-family dwelling. Any project that changes the building envelope such as building a dormer or a new second story is considered an addition. Depending on the scope of work, your project will most likely require electrical, plumbing and/or mechanical permits.
Your permit will be reviewed for compliance with the Portland Zoning Code, the Building Code and other local regulations.
- Applicable City and State Codes: Refer to the Codes page on the Bureau of Development Services (BDS) website.
- Portland’s applicable building code is the Oregon Residential Specialty Code. See the State Codes page for more information about this and other construction codes in effect.
- The Portland Zoning Code, (City Title 33) includes use regulations and development standards, such as maximum building footprint coverage and setbacks, and can be found on the Zoning Code page.
Our "New Users" tab is a good place to start for overall information about the permitting process.
Things to Consider when Planning your Project
1. Researching Building Permit Records for Your House
Before preparing building permit plans, it is important to verify that existing finished space in your house was legally permitted. BDS maintains building permit records that can help you prepare plans for your current house project. Historical inspection cards or microfilmed permit plans may be available to determine the existing “permitted” condition of your house. Although the Multnomah County Assessor maintains information about your house’s living area (available on PortlandMaps.com), this information may not match the building permit history. There is no "grandfathering-in" of unpermitted finished or living areas, and to be considered legal living area, a permit is required.
- Some records are available online, see our Public Records Access page.
- Drawings for many permits issued after June 2012 can be viewed online through PortlandMaps.com under the "Documents" menu for that property.
- Resource Records section maintains copies of past permits on microfilm, which can be viewed in the Development Services Center.
2. Major Alterations and Additions
Projects that add square footage or height to an existing house or duplex may qualify as “Major Additions” depending on the size of the addition and scope of work relative to the existing structure. These types of permits have additional requirements for notification of the neighboring properties and neighborhood association. There is a waiting period between the time of notification and when the permit can be issued, so it is important to plan ahead.
- See the Major Residential Alteration and Addition Permit – Notification and Delay Requirement Information page to determine if your proposed work falls into this category and is therefore subject to these notification requirements.
(3) Included Work, such as Enlarging the Footprint
This page covers projects that expand the house vertically by adding a dormer or second floor. If your project will include other types of work, such as enlarging the footprint or adding a garage, please see those information pages for additional requirements.
Please refer to the Residential Permits summary page for more information.
(4) 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 into living space. It is best to complete your research on the existing conditions before submitting plans for review. Habitable space standards for existing space are explained in Brochure 9, “Converting Attics, Basements and Garages to Living Space”.
(5) Attic Conversions
You must determine if the existing attic floor structure is strong enough to carry the weight of people and furniture.
If converting attic space to living space would mean raising the roof, the Zoning Code height regulations may affect your project.
(6) Residential Engineering
Your project must be designed to meet all structural requirements in the Building Code. The construction drawings must show how both gravity and lateral (wind and earthquake) loads will be resisted. Please see our page on Residential Engineering for more information on these requirements.
Note that plans and calculations will not be required to show that a structure will resist wind and earthquake loads if it can be considered a "minor" addition. See Lateral Bracing for Minor Additions and Dormers. Please note that a “minor” dormer for the purpose of determining lateral bracing requirements may still be subject to the requirements of a “major addition” per City Code Chapter 24.55 (see item 2, above).
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. 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.
If your house is located in a floodplain, there are restrictions that may limit your ability to add to or significantly improve your house without retrofitting it to be flood-resistant. Please contact Site Development staff at (503) 823-6892 to discuss your project.
Permit fees are based on the fair market value of the work included in the permit.