Do You Need a Permit to Build a Deck?

Short answer: often yes. The model residential code exempts only a deck that is 200 square feet or smaller, no more than 30 inches above the ground at any point, not attached to the house, and not serving the door you use to exit. Miss any one of those and you need a permit. Many cities are stricter than the model code, so check yours.

The four conditions for skipping a permit

Under the International Residential Code, which most states and cities build on, a deck needs no permit only when all four of these are true:

• It is 200 square feet or smaller in area.
• No point of it is more than 30 inches above grade.
• It is not attached to a dwelling.
• It does not serve the exit door the house requires.

A low freestanding platform in the yard can meet all four. A deck bolted to the back of the house, or one that sits 4 feet off the ground on a slope, cannot.

Why attached decks always need a permit

When a deck is fastened to the house, the connection at the house wall, called the ledger, carries real load. It is also the connection that most often fails. Nails alone are not acceptable in modern codes, so the drawings show the bolting, flashing and spacing that let an inspector check it directly.

Check your local rule, not just the model code

The model code is a starting point. Cities and counties adopt it with their own changes, and some set a lower height, a smaller area, or require a permit for any deck with stairs or railings. Your building department can tell you in one phone call. Exemptions also do not cancel other rules: setbacks, flood zones and critical areas can still apply to a deck that needs no building permit.

What a deck permit set usually includes

• A site plan showing where the deck sits and how far it is from property lines.
• A framing plan with joist, beam and post sizes and spacing.
• Footing sizes and depths. The depth depends on your local frost depth, which can be a few inches in the South and several feet in northern states.
• A ledger and house connection detail, with flashing.
• Guard, stair and handrail details.

The 2021 model code added more detail on deck design, including snow load, the area each footing carries, post height and guard details, so recent submittals tend to be more specific than older ones.

When engineered drawings help

Many building departments accept a standard plan for a simple deck. Engineered drawings are usually needed when the deck goes beyond the standard tables: a tall deck, a long span, a hot tub or other heavy load, a roof or cover, poor or sloping soil, or an unusual connection to the house. An engineer’s calculations and seal give the plan reviewer what they need to approve it.

What it costs

Deck permit drawings start at $1,699, with a fixed scope and price confirmed before work begins. See the deck permit drawings page for what is included, or the pricing page for every service.

Next step

Send a photo of the area, a rough size, the height above the ground, and whether the deck attaches to the house. We tell you whether you need a permit, what the drawings need to show, and the price, before you pay anything.

Sources

• 2021 International Residential Code, Section R105.2: Work exempt from permit (International Code Council)

This article is general information. Your building department sets the permit rules for your property. Checked October 2026.