Any project that enlarges the footprint of an existing building is an addition and requires a building permit. Depending on the scope of work, your project will most likely need electrical, plumbing and/or mechanical permits.
What you need for a residential addition permit
You will need a completed building permit application, a site plan (often called a plot plan) and architectural plans. Review the plan drawings requirements:
- Drawings, drawn to scale where necessary to verify compliance with code.
- Drawings may be handwritten/drawn if clear and legible. Text or note shall be in print.
- Minimum drawing size: 11x17. All required information is to be clear and legible. Minimum printed text is to be 3/32” or the equivalent 12-point font.
- Cannot use professional's drawings without the permission of the professional who signed the original drawings. For example, an architect’s stamped plan set cannot be used without their permission.
Depending on the scope of work, you may also need structural calculations.
If your project qualifies as a Major Residential Alteration and Addition (MRAA), there are additional requirements including a delay period and notification to neighbors and neighborhood associations. Review the MRAA webpage for more detail on these requirements.
Who can do the work
Contractors must have a license to work in Oregon. The Oregon Construction Contractors Board (CCB) issues licenses to contractors. The permit application and their company materials must list the license number. Need help finding a contractor? The CCB website has good tips on how to search for one. Plumbing and electrical contractors have additional license requirements.
If you are a homeowner doing the work yourself, then you can sign the trade permit applications. You can only do the electrical work if you own and occupy the home and are not planning on selling or renting within 6 months. The State of Oregon has some helpful information for homeowners:
Building permit application and other information needed for a residential addition building permit
The following information is part of the application. This is everything you might need when applying for a permit to construct an addition. Since every project is unique, there may be some situations where you will be asked to provide additional information. Things you need to apply for this permit may include some or all of the following.
If you aren't sure what you need, contact the Permitting General Information phone number. You also might want to read our step-by-step guide for completing a building permit application.
Building permit application
Completeness Checklist: Residential Additions and Alterations for Life Safety and Structural Review (Fillable)
Download the Word document and save a copy to use this form:
Disclaimer for Existing On-site Sewage Disposal System
Erosion control plan
- If the project will result in disturbing the ground with mechanical equipment
- If the project qualifies as a complex site
- The erosion control plan can be part of the site plan
Major Residential Alterations & Additions permits have additional requirements
Mitigation form and/or a stormwater plan (simplified approach form)
If your project will add more than 500 square feet of impervious area:
Residential system development charge (SDC) form
Sample site plan
Simple site erosion control requirements form
If the project will result in disturbing the ground with mechanical equipment and if the project qualifies as a simple site (less than 10% slope, more than 50 feet from a wetland or waterbody and outside an environmental or greenway zone:
Structural plans and calculations
Temporary excavation guidelines
2017 Energy Efficiency Additional Measures Requirements
W-3 form: small meter sizing worksheet
If project will result in more than three bathrooms on site:
For combination permits (if applicable)
Step 1: Research your property and what you need for your addition project
Residential addition building permit code and rules
Permits are reviewed under multiple city and state codes including:
Other codes may apply based on the scope of work. The City and State Codes, Administrative Rules, Code Guides and Program Guides web page has the codes, administrative rules, code guides and program guides.
How to check the permit history for a house
Depending on the age of your house, we may have inspection cards or microfilmed plans that show the permit history for your house. It is important to verify the permit records, not rely on the tax information from the county assessor’s office. If "existing” living space was not permitted, it will need to be legalized through a new permit. To be considered living space, you would need to submit for the same conversion permits as if the work was not already done.
Some records are available online, visit our How to Request Public Property Records webpage.
Planning and Zoning
Before getting started, contact the Zoning Information Line phone number to find out what is allowed on your property. There are rules about maximum building coverage and required setbacks that could impact your project.
Major Residential Alteration and Additions (MRAA)
A major residential addition is adding more than 500 square feet of new interior space by expanding the building footprint or envelope. A major alteration means removing 50% or more of the exterior walls above the foundation.
Major Residential Alterations and Additions have a notification rule. There is also a required delay period. (Portland City Code Section 24.55.210). For more information about Major Residential Alteration and Addition permits (MRAA):
Adding an upper story or an ADU, converting unfinished space or building a new garage
The information on this page is for additions and enlarging the building footprint. If your scope of work includes adding a garage, adding an upper story, or conversion of unfinished space into living space, there are important things to know that can impact your project:
- If your work includes a new garage, review Garage, Shed and Accessory Structure Residential Building Permits for additional requirements.
- If you are also Increasing the building envelope by adding an upper story, review Dormer or Upper Floor Addition Residential Permits for additional requirements.
- If you are also converting unfinished space into living space, visit the Attic, Basement or Garage Conversion Residential Building Permits webpage for additional requirements.
- If your project includes and Accessory Dwelling Unit (ADU), visit the ADU Permits webpage for additional requirements.
When you need a building permit and trade permits for a project (combination permits)
The Bureau of Development Services sells a "Residential Combination" permit package. This allows you to call for all inspections using one Building Permit (RS) IVR number. You can also pay for all the permits at one time. If you choose a combination permit, you will need to submit the trade (mechanical, electrical, and/or plumbing) applications with your plans. If you are hiring subcontractors to do the trade work, they must sign their trade permit application.
Decommissioning a septic tank or cesspool
If you are building an addition, and the house was not connected to the sewer when it was built, you will likely need to decommission the cesspool or septic tank.
Be careful when digging near the property line for construction. The work should not cause damage to the next door property and buildings. The temporary excavation guidelines has information on requirements.
If your house is located in a floodplain, there are restrictions that may limit your ability to add or to significantly improve your house. The work may require retrofitting your house to be flood resistant. Flood plain information is available on Portland Maps Flood Hazard gallery. If the property is located in a flood plain, talk to Site Development Permits & Inspections in the early stages to find out what you need.
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 review the Structural Engineering webpages for more information on these requirements.
Permit fees are based on the type of permit, the work proposed, the valuation of the work, and the staff that need to review the work.
Step 1b: Still need help? Schedule a 15-minute appointment
This is an optional step. If you still need help, we are here for you if you have questions about the information and materials you need to apply. You can schedule a free 15-minute appointment with any of these reviewers:
- Meet with a City Planner to receive information about planning and Zoning and Tree Code requirements that apply to your property.
- Meet with a Building Code and Engineering Reviewer toget help with building code and engineering requirements.
- Meet with a Permit Technician if you have questions about the permit process or if you need help with application requirements.
- Meet with a Water expert tofind out if your project requires you to increase the size of your existing water meter.
- Meet with a Transportation expert to find out if your project will trigger right-of-way improvements.
Contact Environmental Services if you have questions about sanitary or stormwater sewer lines: 503-823-7761.
If you need help, these are experts we recommend you meet with for this project. Not all review groups are listed. The groups listed above will help get you started.
Step 2: Apply for a residential addition building permit and check the status of your permit
If you are unable to create electronic plans, please call us and we will work with you.
Step 3: Learn about the plan review process and corrections (checksheets)
Many people might review a single permit. The Permit Review Process web page has more information about the groups who review permits.
A checksheet is sent to the applicant when a reviewer needs additional information or a correction has to be made to the plans. Read more about how to send us corrections and how to prepare corrected paper plans.
Step 4: Get your residential addition building permit
We'll contact you when your permit is ready, and let you know about any fees due. You'll get instructions for how to get your approved permit and pay your fees. Your permit is not issued until all fees are paid. Read more about the pre-issuance process.
Step 5: Start building and get ready for inspections
The inspection card lists all the inspections you will likely need during your construction project, and what work needs to be done first. Anything having to do with walls, floors, ceilings, stairs, roofs is structural. These need to be inspected before they are covered in any way, or before pouring any concrete.
For combination permits including electrical, mechanical and plumbing, visit the trade permit webpages for information on the order of inspections.
All permits need a final approval inspection to be complete.
Step 6: Residential inspections, results and corrections
To schedule an inspection, call the automated Requests for Inspection phone number. You will need your IVR or permit number and the three-digit code for the inspection.
Get the results of the inspection on Portland Maps permit/case search the next day.
Read more about why work does not get approved and how to schedule a reinspection.
Contact residential inspectors about your residential permit inspections
If you have questions before or after your inspection, you can talk to an inspector.