MDK Permitting › Permit guides
Do I need a permit for a deck in Oregon?
Most decks do. Small, low, freestanding decks usually don't. Here's how to tell, and what it costs in the Portland metro area.
When does a deck need a permit?
In Oregon, a deck usually needs a building permit if any of these are true: it's over 200 sq ft, any part of it is more than 30 inches above the ground, it's attached to the house, or it serves a door you'd need to get out in an emergency. Your city or county makes the final call, and some add their own rules.
When doesn't it?
A small deck (200 sq ft or less), under 30 inches off the ground at every point, not attached to the house, and not serving an exit door is usually exempt. It still has to meet code and zoning setbacks.
Does a deck need an engineer?
Most standard decks don't. Second-story decks, big spans, hot tubs on a deck, or decks on steep slopes often do. We draw the engineered plans and a licensed Oregon professional engineer stamps them, about $200 at cost.
What do you need from me?
Rough size and height, where it attaches to the house, a few photos of the spot, and your address. We measure and draw the rest.
What it costs
Our price, plus city permit fees worked out from each city’s published fee schedule. City fees are paid to the city and the final amount is set at review. Construction isn’t included.
| Example | MDK price | Washington County | Hillsboro | Portland | Clackamas County | Marion County |
|---|---|---|---|---|---|---|
| 300 sq ft deck, 30 in. to 8 ft off the ground Building permit | $950 plans, engineering & permits | About $795 | About $215 | About $655 | About $295 | About $245 |
| 250 sq ft second-story deck Building permit | $1,275 plans, engineering & permits + engineer stamp about $200 | About $760 | About $200 | About $625 | About $270 | About $230 |
County columns are for areas outside city limits. Other cities have their own fees. Get your exact numbers with the price builder.
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More permit guides: Retaining walls · Outdoor stairs · Porch & patio covers · ADUs & garage conversions · Additions · Panels, EV chargers & hot tubs · Load-bearing walls · Sheds & fences
General guidance for Oregon homeowners. Rules vary by city and county, and the building official makes the final call. Prices checked against published fee schedules in November 2026.