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Structural Design Requirements for 1 and 2 Family Residential Structures

Get information about structural and engineering requirements for 1 & 2 family residential projects in the City of Portland.

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Your project needs to meet all the requirements of the building code.  The structural requirements for residential projects may be designed using either prescriptive methods or needs to be engineered by a registered design professional.   

Building Code and Rules

Building Codes, Rules & Guides has links to the codes and administrative rules, code and program guides.  

Engineered Path

If your design does not meet the prescriptive path, you will need a licensed engineer, certified in Oregon. They will need to prepare engineering calculations and drawings to show the structure can resist vertical and lateral loads in accordance with the Oregon Structural Specialty Code (OSSC). Refer to commercial permits for information regarding engineered residential design.

Deferred Submittals

Click here for information, guidelines and requirements for deferred submittals.

Gravity loads

There are also requirements for resisting gravity loads, and any beam over 10’ long or supporting a point load must also be submitted with beam calculations.

Lateral loads

There are two options in the Building Code to show the building will resist lateral loads (wind and earthquake forces). Note that plans and calculations are not needed to show that a structure will resist wind and earthquake loads for a "minor" addition - Lateral Bracing for Minor Dormer Additions

Prescriptive Path

In the prescriptive path,  the ORSC (Oregon Residential Specialty Code) provides conservative method of construction to ensure the building will resist wind and earthquake loads using braced wall panels, continuous sheathing and tie-down anchors. If your structure is designed to meet prescriptive requirements for lateral design, you will need to include separate wall bracing floor plans. 

Prescriptive Design Values

The following are design values that may be used for prescriptive residential design:

Wind: Applicable design wind pressure is 18 psf (ASD).
Seismic: Applicable Seismic Design Category is D1.

Other helpful resources for residential permitting 

Solar Installations :  


Building Code Plan Review

Development Services

phone number503-823-1456

Monday through Friday from 8 am - 5 pm. Leave a message with detailed information.

Structural Engineering Plan Review

Development Services

phone number503-823-1302

Monday through Friday from 8 am - 5 pm. Leave a message with detailed information.