Fort Collins CO Deck Permit Rules

Fort Collins Deck Permit Rules

A Fort Collins deck needs a permit if it is attached to the house, more than 30 inches above grade at any point, larger than 200 square feet, or serving the front door, and the fee is $110 plus sales tax. This guide sets out the City's 2026 rules: what triggers a permit, which repairs count, what the plans must show, when an engineer has to stamp them, and the inspections that follow.

Last reviewed November 2026.

When a Fort Collins deck permit is required

The City's Residential Deck Guide lists the conditions. Any one of them means a permit:

Any deck or porch landing that serves the front door.
Any deck more than 30 inches above grade at any point.
Any deck attached to the house at any point.
Any deck more than 200 square feet.
Replacing joists, posts, beams or stairs.
Replacing the guard railing.
Replacing decking boards with boards heavier than the old ones.

The last three catch many homeowners: they make most structural deck repairpermitted work, and they mean switching an old pine deck to a heavier composite or hardwood surface needs a permit even on the same frame. The guide covers exterior concrete stairs, ramps and landings too, and it isn't for apartment or condo buildings of three or more units.

What the City wants to see

Fort Collins deck permit submittal (all PDFs)

Document	What it shows
Permit application	Deck square footage and any other work, such as lights or outlets
Homeowner affidavit	Only when the homeowner is the builder
Site plan	Deck location, size and distances to property lines and other structures
Floor plan	Piers, posts, beams, joists, ledger, stairs and guards, with spans, spacing and tributary areas
Side view	Deck height, post height, pier depth, guard height and spacing, stair treads and risers
Connection details	Lateral connection, ledger, flashing, joist, beam-to-post and post-to-pier connections
Before photo and info sheet	Where the deck will go; wood species, member sizes, spans, decking material

Source: City of Fort Collins Residential Deck Guide, revised 6.24.2026. Plans may be hand drawn but must be to scale. Code tables are read at 40 psf live load and 1,500 psf soil bearing.

Pier depth is the number people get wrong: 30 inches minimum for a deck attached to the house, which is the City's frost depth, and 12 inches for a freestanding deck. Diameters by tributary area are in the footing depth and snow load guide.

Three workers building new deck framing, with joists and blocking set on posts in a backyard — New deck framing going in: joists, blocking and beams before the boards.

When an engineer has to stamp the plans

Plans for these decks must come from a Colorado-registered professional engineer or an engineering architect, hired separately:

Multi-story or stacked decks.
Beams supported by hangers, including beam-to-beam and beam-to-house hangers.
A ledger attached to a cantilever or overhang, such as a bay window bump-out.
Decks supporting a hot tub or pool.
Diamond Piers on second-story or higher decks, or decks more than 10 feet tall to the top of the beam.
Steel decks outside the code's steel section, or steel decks west of Overland Trail, the over-140 mph wind area.
Materials or designs the code doesn't address, and specialty piers such as helical piers.
Patio covers or pergolas bearing on top of the deck.
Floating stairs hung below the joists, or stairs attached with strapping.

In practice an engineer sees every hot tub deck, most second story decks on stacked or tall framing, and any covered deck whose roof rests on the deck framing. A cover on its own posts and footings is not on this list. Pergolas and patio covers have their own guide, summarized in the Fort Collins pergola permit guide.

Inspections

In order

Once the permit is issued: setbacks and footings with the pier holes open, before any concrete; foundation and post connections; rough frame, called in before decking goes down, with every connection visible; rough electrical if any; then final inspection and final electrical. Decks built with concealed connectors may need more than one rough-frame visit.

Details inspectors check

Guards where the deck is 30 inches or more above grade measured 3 feet out, openings under 4 inches, cable at 3 inches maximum with posts 4 feet apart, stairs at least 36 inches wide, landings at top and bottom, a light at the top landing (new fixtures shielded and aimed down), 36 inches of clearance over any egress window well, and corrosion-resistant fasteners on treated lumber. The railing and stair code guide has the stair numbers.

Stained wood deck with railings and stairs looking over a backyard in autumn — A stained wood deck and stair railing in autumn.

Fort Collins Deck Permit: Questions

Concrete being pumped into a square footing hole, with steel reinforcing bars beside it

Concrete going into a footing hole.

Do you need a permit to build a deck in Colorado?

Colorado leaves it to each city and county, and most Front Range jurisdictions require one for anything but a small, low, freestanding deck. In Fort Collins a permit is required for a deck that is attached to the house at any point, more than 30 inches above grade at any point, larger than 200 square feet, or serving the front door. Larimer County outside city limits requires one above 30 inches or when the deck is the main entry or exit.

How much is a deck permit in Fort Collins?

$110 plus sales tax: a $38.50 plan check fee paid when you apply and a $71.50 building permit fee paid when the permit is issued, per the City's building permits page.

What size deck can I build without a permit in Fort Collins?

A deck of 200 square feet or less that is no more than 30 inches above grade at any point, not attached to the house, and not serving a required exit door. Setbacks still apply, and replacing joists, posts, beams, stairs or guards on any deck needs a permit.

Can a homeowner pull a deck permit in Fort Collins?

Yes. Homeowners building their own deck submit a homeowner affidavit with the application. Contractors must hold a Fort Collins license in a class the City allows for decks: A, B, C, C2, D, D2 or MM, and MM doesn't cover two-story decks.

What inspections does a Fort Collins deck get?

Setbacks and footings with the pier holes open, before concrete; the foundation and post connections; rough frame before any decking is installed, with every connection visible; rough electrical if there is any wiring; and the final. Concealed connectors can mean more than one rough-frame visit.