Basement finishing in Arvada under the city's new 2024 codes

What Arvada's 2024 code update means for a basement finish

City Council approved the 2024 International Building, Residential, Plumbing, Mechanical and Fuel Gas codes in March 2026, along with the Colorado Low Energy and Carbon Code and the 2026 National Electrical Code. The change took effect July 1. Permits submitted before then could still use the 2018 codes, and projects already under a permit in good standing are not affected.

The best-known piece of the package, a sprinkler mandate, applies to new single-family homes, duplexes and townhomes. Arvada says plainly that it will not affect existing structures, additions or remodels.

The city's summary of the changes also notes that the 2024 residential code can waive egress windows in basement sleeping rooms where a home is sprinklered. That exception carries conditions, and it mostly matters for houses built under the new rules. In an existing, unsprinklered house, a basement bedroom still means an egress window.

One permit covers framing, trades and egress in Arvada

Arvada files basement finishes under its Residential Interior permit, reviewed by the Building Inspection Division in Community and Economic Development, all of it handled electronically in eTRAKiT. The single permit includes the mechanical, plumbing and electrical work and any egress windows, so no separate trade permits are issued. Licensed subcontractors attach themselves to it with the city's subcontractor form.

Who needs a license

An owner who lives in the house and does the work personally needs no license. Hire anyone for any part of it and Arvada requires a licensed contractor on the permit, holding a Class B or Class C general contractor license for interior remodels. If the house is not your primary residence, you either hire a contractor or get licensed yourself.

When an engineer joins the drawings

Plans do not need a stamp unless the work includes structural changes or new egress windows. Add an egress opening, move a post or alter a beam, and engineered drawings or an engineer's letter become part of the submittal. A new gas line brings its own requirement: a sizing calculation showing pipe size and material, the tie-in point, run length, meter pressure and the total BTUs it serves. Our design phase assembles all of this before the permit step.

What the floor plan shows

Arvada wants room dimensions and labeled uses, every outlet, smoke and carbon monoxide alarm, light, fan, cleanout and appliance, window sizes and types, egress wells with ladder and clear dimensions, and any dropped ceiling below 7 feet. Hand-drawn plans are accepted at City Hall, where staff scan them into the electronic file.

Arvada houses span more than a century of building

Arvada was platted in 1870 beside the Colorado Central Railroad, near the creek where Lewis Ralston found gold in 1850, and Olde Town still holds the oldest blocks. After World War II the town boomed, with new houses spreading north of Ralston Road between Carr and Independence streets. Interstate 70 opened in 1967. The census counted 2,359 residents in 1950 and 84,576 in 1980.

Newer planned communities such as Candelas and Leyden Rock sit at the city's northwest edge. A 1960s basement and a 2010s basement share a slab and a stair and differ on almost everything else, so the survey changes with the house: duct height and window size in one, a capped plumbing rough-in or a builder's soils report in another.

Clay, radon and Jefferson County ground

About 121,500 of Arvada's 124,402 residents at the 2020 census lived on the Jefferson County side. Jefferson County Public Health puts roughly half of the county's homes above the EPA radon action level of 4 pCi/L, so a test comes before any drawing, and a mitigation stack gets a planned path through storage or a closet.

Expansive clay is the other given. The Colorado Geological Survey notes that yearly losses from swelling soils regularly exceed those from floods, tornadoes, earthquakes and hurricanes combined. So partitions on the slab are framed to slide, hung from the joists with a void at the base that the soils report sizes when one exists.

Fitting rooms to an Arvada basement

Because Arvada's permit bundles egress with everything else, a basement bedroom suite goes through one review that covers the room, the well and the bathroom. In our egress-driven suite study, the well location sets every other wall. Plumbing decides the wet bar: its sink has to reach the main sewer, so we find that line first. Under a low duct trunk in an older house, a flat-floor media room usually beats a riser.

Code editions differ across city lines. Westminster and Lakewood were still reviewing residential work under the 2021 codes when Arvada moved to 2024, so a plan drawn for one city needs a fresh code check before it travels.

Begin an Arvada plan

An address, some photos and the house's age give us enough to confirm which code applies, whether an engineer is needed and where egress can land. Start planning your Arvada basement.