1900 SW 4th Ave, Portland, OR 97201
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 under provisions of the current Oregon Residential Specialty Code. View more information on building codes.
It is recommended to visit or call the Planning and Zoning staff (503) 823-7526 and Buildings staff (503) 823-7310 at the Development Services Center early in the planning of your project.
Checking your House’s History
Depending on the age of your house, we may have permit cards or microfilm on file 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.
The following information must be submitted when applying for a permit to add a dormer or second floor to an existing one or two family dwelling. Since every project is unique, there may be some situations where you will be asked to provide additional information.
|Site Plan (Scale site plans to most appropriate scale, e.g. 1”=10’ or 1/4”=1’)|
|Architectural Plans (Scale of plans to be ¼”=1’ and details scaled to ½”=1’. Single line drawings are not acceptable – plans must be drawn to show wall thickness)|
|Structural Plans (Scale of plans to be ¼”=1’, details to be ½”=1’)|
If you are hiring sub-contractors to do work on your project, and know who they are when applying, they will be listed on your permit at that time. If you don't know when you apply for your permit, they can be added after issuance. Sub-contractors you hire must be registered with the State of Oregon and will carry a current CCB license.
|Things to consider:|
Note: To make conversions easier, the Bureau of Development Services has set up the following special standards for existing situations:
|(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 into living space. It is best to complete your research on the existing conditions before submitting plans for review.
|(2) 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.
|(3) Residential Engineering|
|Your project must be designed to meet all the requirements of the building code. This usually means that a full foundation with footings to the frost depth, and a complete lateral force resisting system are required.
The building code has two options for showing the building will resist lateral loads. More Information on Residential Engineering
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.
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, the ability to do these types of improvements may be severely limited. Please contact Site Development staff at (503) 823-6892 to discuss your project.
After you pay intake fees, your project will be "under review". The bureaus/review groups that will check a typical conversion project are:
The yellow inspection card lists all the inspections you will likely need during your construction project, and what work needs to be done first.
Once your building permit is issued, erosion control measures must be installed, prior to beginning any further ground disturbing activities.