Information on residential addition permits that enlarge the footprint of a single family home or duplex. Get all required forms for a residential addition like adding a bedroom. Find information on permits and inspections and learn more before you add a room to a home or remodel a home.
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.
Required applications and important handouts for a residential addition building permit
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:
- Architectural Plans (Residential Submittal Requirements for Additions)
- Disclaimer for Existing On-site Sewage Disposal System (if building an addition and house has a septic tank or cess pool on site)
- Energy Efficiency Additional Measures
- Erosion Control Plan
- If the project will result in disturbing the ground with mechanical equipment
- If the project qualifies as a complex site
- Can be part of the site plan
- Mitigation form and/or a stormwater plan if your project will add more than 500 square feet of impervious area
- Residential System Development Charge Form
- (if project will result in more than 3 bathrooms on site)
- 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 & Calculations
- For Combination Permits (if applicable):
Step 1: Research your property and what you need for your project
Residential addition building permit code and rules
Permits are reviewed under multiple city and state codes including:
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 Planning and Zoning 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. If the Major Residential Alterations and Additions have a notification rule. There is also required delay period. (Portland City Code Section 24.55.210). For more information, visit apply for a Major Residential Alteration and Addition permit (MRAA):
- Major Residential Alterations and Additions (Brochure 23)
- Major Residential Alteration and Addition Permit - Overview and Criteria
Additional work including garages and adding an upper story
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, visit Garage, Shed and Accessory Structure Residential Building Permits for additional requirements.
- If you are also Increasing the building envelope by adding an upper story, visit Dormer or Upper Floor Addition Residential Permits for additional requirements.
- If you are also converting unfinished space into living space, visit Attic, Basement or Garage Conversion Residential Building Permits for additional requirements.
- If your project includes and Accessory Dwelling Unit (ADU), visit ADU Permits for additional requirements.
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.
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 doing the work your self, 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.
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 & Septic Review in the early stages for what is needed.
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.
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. Permit Fee information.
Step 2: What you need for an addition permit
You will need a completed building permit application, a site 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, there are additional requirements including a delay period and notification to neighbors and neighborhood associations. See the MRAA page for more detail on these requirements.
If you are applying for a combination permit you will also need to submit the trade permit applications (Electrical, Mechanical, and Plumbing).
Each project is unique and you may be asked for additional information.
Step 3: How to submit a residential addition building permit application
If you are unable to create electronic plans, please call us and we will work with you.
Step 4: Plan review process and checksheets
Different departments will review your plans to verify that the proposed work meets requirements.
The bureaus/review groups that will check a typical additon project are:
- Planning and Zoning
- Life Safety Review
- Structural Review
- Site Development Review
- Bureau of Environmental Sciences Review
- Bureau of Transportation
- Urban Forestry Review
- Water Bureau, depending on the number of fixtures in the structure
If a reviewer needs more information, they will send a checksheet to the applicant requesting corrections or more information. The plans will need to be updated and re-submitted with the checksheet response.
The permit review process webpage has more information. You can check the status of the permit review on Portland Maps permit/case search.
Step 5: Residential addition building permit issuance
When the last technical review is approved, your permit will be pre-issued. Pre-issuance is the last permit check. This step ensures all required reviews took place, all required approval stamps are on the plans, and the fees are charged correctly. You will be contacted when your permit is ready, and notified of your final fee total. Instructions will be given on how to get your approved permit and pay your fees. Your permit is not issued until all fees are paid.
Step 6: 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 pages for information on the order of inspections.
All permits need a final approval inspection to be complete.
Step 7: Residential inspections, results and corrections
To schedule an inspection, call the automated inspection request line. 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.
Not approved - there are some reasons why the work did not get approved:
- no access - the inspector may not have been able to inspect the work
- incomplete work
- code violations
The inspector will list the corrections needed on the inspection report.
Call for a reinspection after making the corrections. Use the same three digit inspection code.
If you make the corrections the same day wait until 5 pm to request a reinspection. The inspector needs to enter their results before you can schedule the reinspection.
There is a reinspection fee charged for more than one reinspection for a single issue.
Contact residential inspectors
If you have questions before your inspection, you can talk to an inspector. The 1 & 2 family inspector area map list the inspector's name, area, and phone number.
Because of vacation or illness, your inspector may be different than the one listed on the map. If you have questions after your inspection, find out which inspector to call. Their contact information will be on the inspection results and on Portland maps.