Do I Need a Permit to Build a Deck in Colorado?

No statewide code: every city writes its own rules

Colorado is one of the states that does not enforce a mandatory statewide residential building code. While the Office of the State Architect adopts codes for state-owned buildings — currently the 2024 International Building Code (IBC) and International Residential Code (IRC) — private residential construction falls entirely under local jurisdiction.

Most Colorado cities base their local codes on the International Residential Code (IRC) published by the International Code Council (ICC), but the specific edition they adopt and the amendments they add vary. Denver adopted its own 2025 Denver Building Code based on the 2024 IRC, while Aurora still enforces the 2021 IRC. Colorado Springs uses the Pikes Peak Regional Building Code, a locally developed code based on ICC standards with significant regional amendments.

For homeowners, this means one thing: check with your local building department before you start building. The rules in Denver are not the same as the rules in Fort Collins or Lakewood.

Deck permit requirements vary significantly across the country — see our national deck permit guide for how Colorado compares to other states.

When you need a permit

Despite the city-by-city variation, most Colorado jurisdictions share a common set of triggers based on IRC Section R105.2. You'll almost certainly need a permit if:

• Your deck is more than 30 inches above grade at any point
• Your deck exceeds 200 square feet in area
• Your deck is attached to the house via a ledger board
• Your deck serves as an exit or egress from the dwelling

The 30-inch height threshold is the most widely used trigger. Once a deck reaches that height, guardrails — at least 36 inches tall for residential decks — become a structural safety requirement, and the project crosses into territory that demands plan review and inspection.

When you might be exempt

Small, ground-level, freestanding decks get the most lenient treatment across Colorado. In most jurisdictions, a deck is exempt from permit requirements if it meets all of the following conditions: no more than 200 square feet in area, no more than 30 inches above grade, not attached to the dwelling, and does not serve the required exit door.

The Pikes Peak Regional Building Department in Colorado Springs adds a measurement detail worth noting: they measure the 30-inch height at any point within 36 inches horizontally of the walking surface edge, which can catch decks built on sloping ground that appear low on one side but rise above the threshold on the other.

Even exempt decks must comply with all applicable building codes. The exemption only waives the permit requirement — not the code standards themselves.

How major cities differ

Denver processes deck permits through its Community Planning and Development department. The city adopted the 2025 Denver Building Code, making it one of the most up-to-date jurisdictions in the state. Denver offers an online E-permits system for applications, and the city maintains a real-time dashboard showing current plan review times. Denver requires footings to extend at least 36 inches below grade for frost protection.

Colorado Springs uses the Pikes Peak Regional Building Department (PPRBD), which serves not just the city but also Fountain, Manitou Springs, and unincorporated El Paso County. Simple deck projects may qualify for walk-through review at the counter — a 15-minute per-discipline review that can get you approved the same day. More complex projects go into the standard review queue. PPRBD requires a minimum frost depth of 30 inches, slightly less than Denver's 36-inch requirement.

Aurora enforces the 2021 IBC and IRC with local amendments. The city's Building Division has introduced flat-rate fees for some simple construction projects. Aurora requires 36-inch footing depth, matching Denver. Applications go through the city's online portal, with a pre-acceptance review typically taking two business days.

Fort Collins provides a detailed residential deck guide through its Building Services department. The city requires permits when a deck is over 30 inches above grade, attached to the house, serves the front door, or exceeds 200 square feet. Fort Collins adds a specific requirement: decks attached to brick, masonry, or stone veneer must have stamped engineered plans. Standard plan review takes about 14 calendar days, and permits expire if work doesn't begin within 180 days.

Lakewood has a split approach based on geography. East of Kipling Street, standard IRC load requirements apply — 40 pounds per square foot (PSF) live load, 50 PSF total load. But west of Kipling, in the foothills, decks must be engineered for 155 mph wind loads. Lakewood requires all deck framing to be pressure-treated wood, redwood, or western cedar, and specifically prohibits anchoring ledger boards through brick or masonry. The city guarantees plan review within 15 working days.

Colorado's frost depth and snow load challenges

Colorado's climate creates unique structural requirements for deck construction that go well beyond what builders face in warmer states.

Frost depth varies dramatically by location and altitude. Denver and Aurora require footings to extend 36 inches below grade. Colorado Springs requires 30 inches. Mountain communities can require 48 inches or more — in some high-altitude areas of Park County, the actual frost depth can exceed 10 feet, though prescriptive minimum requirements are typically set at 24 to 48 inches.

This matters because inadequately deep footings will heave during freeze-thaw cycles, shifting the entire deck structure. Colorado's dry climate makes frost heave less severe than in wetter northern states, but it's still a primary concern for any deck with structural footings.

Snow loads add another layer of complexity. The minimum ground snow load in much of the Front Range is around 30 PSF, but this increases significantly with altitude. The Structural Engineers Association of Colorado publishes site-specific snow load data, and some mountain jurisdictions require engineering for all structures. When snow loads exceed 65 PSF, exterior decks must be designed for full roof-level snow loads under the IRC.

If you're building a deck above 7,000 feet, expect your local building department to take a closer look at structural calculations.

Wildfire zones and the new Colorado Wildfire Resiliency Code

Colorado's wildland-urban interface (WUI) zones cover substantial portions of the Front Range foothills and mountain communities. The state adopted the 2025 Colorado Wildfire Resiliency Code (CWRC), effective July 1, 2025, which sets minimum fire-resistant construction standards for WUI areas.

For deck builders in WUI zones, the CWRC introduces specific material and design requirements:

• The immediate zone (within five feet of a structure) requires noncombustible, hard-surface materials
• Deck materials must be noncombustible, fire-retardant-treated wood labeled for exterior use, or composite materials meeting ASTM E1354 fire performance testing
• A minimum 6-inch metal flashing is required at deck-to-wall intersections
• Decks must be enclosed or screened underneath with metal screening
• Gravel ground cover is required under decks

Boulder County, Eagle County, Summit County, and many mountain communities enforce their own WUI codes that may be stricter than the state minimum. If your property is in or near a WUI zone, check with your local fire district in addition to the building department.

Expansive soils along the Front Range

Much of Colorado's Front Range — including the Denver, Aurora, and Colorado Springs metro areas — sits on expansive bentonite clay soil. This soil swells significantly when wet and contracts when dry, creating ground movement that can shift deck footings and damage connections.

Some jurisdictions require a soils report for deck footings in areas with known expansive clay. Pier-type foundations drilled through the expansive layer into stable soil below are common. This adds cost compared to simple poured footings, but prevents the kind of seasonal movement that can rack a deck frame and pull connections apart.

If you're in a clay-heavy area, discuss foundation options with your building department before finalizing your deck plans.

Applying for a deck permit

The general process across Colorado cities follows a similar pattern:

• Contact your local building department to confirm whether your project requires a permit
• Prepare a site plan showing your property boundaries, the proposed deck location, and distances to property lines
• Draw or have drawn construction plans showing dimensions, framing, materials, connections, railing details, and footing depth
• Submit the application — Denver, Aurora, Fort Collins, and Lakewood all accept online applications
• Pay the permit fee
• Wait for plan review
• Build the deck and schedule inspections

Fees are generally valuation-based across Colorado, calculated from the total estimated construction cost using ICC building valuation data. For a typical residential deck, expect fees in the range of $200 to $500 depending on project scope and jurisdiction. Colorado Springs offers an online fee calculator through PPRBD, which can give you a quick estimate before you apply.

Inspections

Most Colorado cities require inspections at key construction stages:

• Footing inspection — before concrete is poured, verifying depth meets frost protection requirements and placement matches approved plans
• Framing inspection — after the structural frame is complete but before decking is installed, checking connections, hardware, and code compliance
• Final inspection — after the deck is fully complete, including railings, stairs, and any electrical work

In Fort Collins and other cities, permits expire if no inspection occurs within 180 days. Schedule your inspections promptly to avoid having to reapply.

What happens if you skip the permit

Building without a required permit in Colorado can result in stop-work orders, fines, and requirements to demolish or retrofit the unpermitted structure. Some jurisdictions charge double fees for retroactive permitting.

Beyond enforcement, unpermitted decks create problems at sale time. Colorado real estate transactions routinely involve property inspections, and unpermitted structures can delay or complicate closings. Your homeowners insurance may also deny claims related to an unpermitted deck.

The permit fee is almost always a small fraction of total project cost. Paying it upfront avoids expensive problems later.

For an overview of all building permit requirements in Colorado — including sheds, fences, and more — see our complete Colorado building permit guide.

If you're also planning a fence or patio alongside your deck, Colorado has separate permit requirements for each — see our guides to fence permits in Colorado and patio permits in Colorado.