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Residential decks

Adding a deck is a great way to enjoy the outdoors and boost your home’s value. These pages explain what permits you need to build a deck at a one- or two-family home, and how to apply. Use the navigation menu to find out more about each step.

Get your custom project guide
A deck attached to the back of large house.View full size image

Get the right forms

Answer our permit questions to help you know what forms you'll need to apply. Find more information on each kind of form and when you might need them.

This page explains when you might need certain forms for your project. You can also answer questions to get a custom project guide for your deck.

Is any part of the walking surface of the deck over 30 inches above the ground?

Sometimes decks may be on uneven ground. Anywhere where the walking surface is measured over 30 inches from the ground, you’ll need a building permit. Take this measurement 36 inches from the perimeter of the deck.

For all deck projects that require a building permit you'll need:

You'll also need to include with you application:

Don’t want to draw your own structural plans?

Requirements for using the permit-ready deck plans

To use the permit-ready plans, your project must meet all of these conditions:

  • Single level – The deck has only one level.
  • Attached to the house – It connects to an exterior wall.
  • Wood frame – The deck structure is made of wood.
  • No heavy finishes – The deck surface does not support concrete, tile, or other heavy materials.
  • No heavy loads – The deck does not support a hot tub or other large concentrated loads.
  • Simple rectangular shape –
    • The deck is rectangular.
    • It has one row of posts or columns supporting the outer edge.
    • Deck joists have a single span but may cantilever past the edge beam.

⚠️ Important: Review the limitations of use on sheet S1 of the permit-ready plans before you begin.

Deck Design Guide: Permit-Ready Plans9.48 MB

Is there a septic tank or cesspool on your property?

Not sure? Here's how to check:

  1. Go to PortlandMaps.com.
  2. Enter your address.
  3. Navigate to Permits & Zoning.
  4. Click Permits.
  5. You may have Historic Plumbing records.

If you don't see a Historic Plumbing section, we recommend requesting public records.

After you search, if you’re still not sure, call us at 503-823-7300 or email septic@portlandoregon.gov for help.

In use: Active septic tanks or cesspools

You cannot build the deck foundations within 10 feet of the tank.

You will also need to acknowledge there is a septic tank on your site as part of your permit application.

Not used: Abandoned septic tanks or cesspools

Is the house currently connected to public sewer and the septic tank or cesspool is no longer used? 

Will you be digging up the ground?

Determine if your project is on a simple site.

Sites that are considered a simple site must meet all of these criteria:

  • The ground is mostly flat (less than a 10% slope where work will happen).
  • The project will disturb less than 10,000 square feet of land.
  • The site is more than 50 feet away from any wetland or body of water.
  • The project does not involve dividing land that’s 10,000 square feet or larger.
  • The site is not in an Environmental, River, or Greenway overlay zone.
  • The site has no known contamination.
  • The project does not involve pumping groundwater offsite (dewatering).

Did your site meet all the simple site criteria?

  • ✅ Yes - and your project will expose 500 square feet or more of bare ground:
  • ❌ No - your site is considered complex.
    • You must include graphical erosion and sediment controls on your site plan.
    • This applies even if you are exposing less than 500 square feet of the ground.

Do you need to prune or remove any trees during your project?

You might need a permit to prune or remove a tree, even on private property. Trees on public property are called "street trees."

For more information and to apply for a tree permit, see the following pages:
 

Will the property owner do the construction work?

The homeowner can do the work and act as the general contractor.

The homeowner must be the recorded property owner by the County and not an LLC.

You’ll need the Owner Doing Work Form.

Owner Doing Work Form - Property owner statement regarding construction responsibilities187.13 KB

Check the third box, fill out the rest, and submit it with your permit application. 

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