Any project that enlarges the footprint of an existing building requires a building permit. Enclosing a porch or adding new living space to your house are examples of projects that require a building permit. Depending on the scope of work, electrical, plumbing or mechanical permits may also be required.
Your permit will be reviewed for compliance with the Portland Zoning Code, the Building Code and other local regulations.
- Applicable Cityand 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. The 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 an Attached Garage or Additional Floor
If your project will include the addition of a garage, please also see our page on Garage, Shed and Accessory Structures for special requirements.
Additional requirements may apply if the scope of work includes converting existing unfinished space to living space, or adding a dormer or additional floor to the house. Please refer to the summary page for more information.
4. 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.
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.
6. Decommissioning a Septic Tank or Cesspool
When enlarging the footprint of an existing structure, septic tank/cesspools must be located and shown on the site plan.
Visit the records staff at the Development Services Center to research plumbing records showing septic systems/cesspools
- If the septic system/cesspool has been decommissioned, and is within 10 feet of the new structure, you must sign a disclaimer for on-site-sewage disposal system form.
- If the septic system/cesspool is within 10 feet of the new structure and has not been pumped and filled, it will need to be decommissioned.
Call Environmental Soils staff at (503) 823-6892 for more information on decommissioning septic tanks and cesspools.
Permit fees are based on the fair market value of the work included in the permit.