Residential decks

Be sure to show the finished grade elevations on your plans. They should show how the ground will look after your project is done.

What to show on your plans:

• Elevations at property corners and building corners.
• Contour lines at two-foot intervals to show changes in ground level.
• Existing grade lines (typically light grey or dashed).
• Finished grade lines (solid black).
• Retaining walls (if proposed) with top and bottom elevations.

How to show it:

• Use 100.0' as a base value for elevation.
• Adjust for changes:
  • Downward slope: Subtract the elevation change.
    • Example: A 2-foot drop = 98.0' (100.0' - 2.0').
  • Upward slope: Add the elevation change.
    • Example: A 2.5-foot rise = 102.5' (100.0' + 2.5').
• Contour lines for larger changes:
  • If the slope changes by 2 feet or more:
  • Show where the change occurs with contour lines.
  • Add a contour line for every 2-foot elevation change. This is common for gentle changes.
  • Use more lines for steep slopes.

If yes, and your property is 5,000 square feet or larger in area, tree protection is required to build a deck.

Tree protection

To protect trees during construction and any digging or ground work, set up a root protection zone around the trees you're required to protect.

Show on your plans:

• Size, location, and species of all trees 12 inches or larger
• Root protection zone radius (one foot per inch tree diameter)
• Fence materials and location
  • Standard fencing
    • Fencing is six-foot high metal chainlink fence.
    • Secured the fence with 8-foot metal posts in the ground.

Repair and replacement of an existing deck that is not changing in size does not require tree protection unless you remove on-site trees as part of the permit. 

Trees to be removed

• We need to know if you plan on removing any trees for development.
• Fees apply for trees over 20 inches in diameter.
• Removing trees 36" or larger requires public notice and fees.

Find it

For replanting guidelines for street trees, refer to:

• Street Tree Planting Standards
• Approved Street Tree Planting Lists

Show on your plans

• Mark trees for removal with an “X”
• Include tree size, species, and location
• Follow replanting requirements as needed

Get help

• Questions about trees on private property?
  • Schedule a 15-Minute Appointment with a City Planner.
     
• Questions about street trees?
  • Email trees@portlandoregon.gov
  • Call 503-823-TREE (8733)
  • Schedule a 15-Minute Appointment about trees on the right-of-way.

We’ll need you to clearly mark and label overlay zone lines with the overlay zone letter on your site plan.

Please schedule a 15-minute appointment with Site Development to discuss the floodplain development requirements for your project.

A survey prepared by a licensed surveyor or professional engineer may be required.

What to show on your site plan:

• The boundaries of the flood hazard area and the base flood elevation.
• How the project will be protected from flood damage.
• How flood storage compensation requirements are met.

Didn't meet all the criteria for a simple site? If you identified that your site is complex, you'll need to include erosion control methods on your site plan.

• Here’s an example of how to do that.
• You should also include narrative elements that give enough detail about how you’ll manage loose soil. Construction notes on the site plans will work well.

Here’s an illustrated manual that helps explain erosion control techniques.  

🚨 Keep in mind that you’ll need to schedule inspections before the digging begins. More information is in the inspections section.

Covered decks count as part of the building. Even if the deck is 30 inches or lower to the ground, a roof or cover increases building coverage. The covered deck must follow setback rules. Zoning treats covered decks like an extension of the house.

Please contact our zoning staff to discuss your project.

• Call 523-823-7300
• Schedule a 15-minute appointment

Be sure to mark the easement and label its purpose.

If all requirements are met, you can use the permit-ready plans for residential decks to provide your structural information.

These plans include important details that you can use instead of drawing your own.

You can choose one of two paths:

• Prescriptive path – Follow the standard construction rules and details provided in the code.
  • What code? Use the Oregon Residential Specialty Code (ORSC) section on decks.
• Engineered path – If your project doesn’t meet the prescriptive rules, you’ll need structural calculations and detailed plans.
  • It might be beneficial to work with a Registered Design Professional licensed in Oregon.

If you’re creating your deck plans, here’s what you need to know.

1. Determine if you need an engineer or architect

   • Does your deck follows all the prescriptive rules in the Oregon Residential Specialty Code (ORSC)?
     • Yes, your deck follows all the prescriptive rules. You do not need an engineer or architect.
   • Does any part of your deck not follow the prescriptive rules?
     • Yes, some parts of your deck does not follow the prescriptive rules. You’ll need structural calculations and detailed plans. It might be beneficial to work with by a Registered Design Professional (architect or engineer) licensed in Oregon.
   • Special note on guardrails:
     • Using glass, cable, steel, or aluminum guardrails?
       • Yes. You’ll need detailed drawings and stamped calculations from the manufacturer.

2. Plans and details you must include

   When you draw your plans, they must include:

   • Framing and foundation plan
     • Show deck dimensions, framing layout, spacing, and sizes for joists, beams, posts, footings, and stairs (if you have them).
   • Elevation view
     • Show a side or front view of your house with the proposed deck, ground level, and the height of the deck above grade.
   • Construction details
     • Joist-to-beam connection
     • Post-to-beam connection
     • Post-to-footing connection
     • Lateral support method and connection
     • Rim joist connection
     • Ledger board attachment
     • Guardrail height, spacing, and post attachment
     • Stair and handrail details (if applicable)

3. Determine if your plans need a stamp

   • Will an architect or engineer prepare your plans?
     • Yes. They must include their professional stamp.
   • Are you required to provide calculations (for non-prescriptive designs or special guardrails)?
     • Yes. A design professional must stamp the calculations.