Turn a Carport Into a Garage: Code Changes and Costs

Can you turn a carport into a garage?

A carport can be turned into a garage when the frame, the floor and the lot allow it, and the change reclassifies the structure. San Diego Information Bulletin 205 (August 2022) and Minnesota Rule 1309.0309 both say a carport must be open on at least two sides, and a structure with fewer open sides is a garage. San Diego requires a building permit to enclose an existing carport. Spokane's guide sheet (2015 International Residential Code with Washington State amendments) requires a concrete surface when a carport with an asphalt floor is converted, and bars openings in a wall less than 3 feet from a lot line. Fine Homebuilding's 2023 summary of the 2021 International Residential Code adds a noncombustible floor that slopes to the vehicle door or a drain, half-inch gypsum board on the walls shared with the house, and a self-closing, self-latching door. Jurisdictions adopt code editions locally, so the building department for the address makes the final call.

The same question comes in several wordings: turn a carport into a garage, convert it, enclose it, close it in. All of them lead to the same test, which is the count of open sides, and to the same short list of changes that follow once the count drops below two.

For how the two structures compare outside the conversion question, read the carport versus garage guide.

What the code changes when converting a carport into a garage

Converting a carport into a garage changes six things the cited documents regulate. They are the floor surface, the floor slope, the wall shared with the house, the door to the house, openings near a lot line and the electrical system.

This page gives general information drawn from the public documents cited above. Building codes, permit rules and prices differ by location and change over time. Confirm the current rule for your address with the building department that issues permits there, and get a written quote from a licensed contractor for your project.

Floors change first. A carport may keep an asphalt floor in Spokane, but the guide sheet requires a concrete surface once such a carport is converted. Fine Homebuilding adds that garage floors under the 2021 International Residential Code are noncombustible, which rules out asphalt, and slope to the main vehicle door or a drain.

The wall and door shared with the house carry the fire-separation rules. Fine Homebuilding lists half-inch gypsum board on walls shared with the house and five-eighths-inch Type X board on a ceiling below habitable space. It also lists a door that is solid wood, honeycomb steel or rated for at least 20 minutes, self-closing and self-latching.

Near a lot line, the Spokane guide sheet allows no openings in a wall less than 3 feet away, and the San Diego bulletin allows openings up to 25% of the wall area from 3 to 5 feet. A garage door is an opening, so the door wall decides whether a conversion fits the lot.

The electrical rules follow the vehicle bays. Fine Homebuilding describes a receptacle for each bay on a ground-fault circuit interrupter (GFCI), carbon monoxide alarms outside bedroom areas in houses with an attached garage, and door openers listed to UL 325.

Gunderson Engineering (May 2025) explains that an engineer classifies a building as open, partially enclosed or enclosed for wind design, and that the class changes the internal pressure used in the calculation. Closing in a carport can therefore change the wind figures its frame is designed for.

How much does it cost to turn a carport into a garage?

Three 2026 guides price a carport-to-garage conversion differently: Angi averages about $22,000, HomeGuide $25,000, and Block Renovation $15,000–$25,000 for most projects.

Figures are the ranges each guide published on the date shown. Each guide covers a different scope, so the columns are not interchangeable.

The guides disagree because they count different things. Block's permit line includes inspections and the entry door, and its door line includes the opener. Angi's door line is the door alone, and HomeGuide's door line covers materials and labor and lists the opener separately at $300–$900. A reader comparing columns is comparing scopes as well as prices.

HomeGuide's average assumes a basic conversion: an existing concrete slab, budget siding, minimum insulation, no windows, a basic door and minimum electrical work. It prices a slab at $4–$8 per square foot installed and a panel upgrade at $850–$4,000 as separate lines, and Block prices a new 20x20 slab at $4,000–$8,000 depending on region.

Arithmetic on the guides' own figures: Angi's highest total of $55,000 is more than nine times its lowest total of $6,000, and the permit line runs from $500 at HomeGuide's low end to $3,000 at its high end.

Slab work is priced by area at Angi and HomeGuide, so footprint matters. The carport size guide lists the square footage of common sizes. For each cost line in more detail, read the carport to garage conversion cost.

What a converted carport does to value and assessment

Value and assessment depend on questions the guides answer unevenly. Los Angeles County Public Works says an addition built without permits must meet current codes when it is permitted later, so a conversion done without a permit carries that cost. In California, the Board of Equalization treats new construction as reassessable at full cash value on completion, and that is a California rule.

Block Renovation prints resale-recovery percentages for garage additions and names no source for them, so this page prints none.

Turning a carport into a garage: FAQ

HOA covenants, electrical and plumbing permits, zoning variances and heating or cooling the new space are outside this page. Each depends on the address and the project, and the association or department involved can answer it.

Last verified October 5, 2026