The carport you find on Pinterest is usually rated for sunshine and good intentions. Real do it yourself DIY carport plans have to account for snow load in your zip code, wind uplift from your nearest weather station, and a permit office that wants stamped drawings if the footprint exceeds 200 square feet. None of that is hard — but skipping it means rebuilding after the first February ice storm. Here is the design path I walk clients through: code-driven, lumber-honest, and buildable in two weekends with a helper.
Sizing the Footprint to the Vehicle
A single-car carport needs at least 10 by 20 feet to clear a midsize SUV with the doors open. Two-car layouts want 20 by 20 minimum, 22 by 22 if either driver is teaching a teenager to park. For a single full-size pickup, plan 12 by 24. Vehicle length plus four feet of working space on each end is the rule that keeps the structure usable in ten years when you replace the car.
Headroom matters too. Spec 8-foot clear from finished grade to the bottom of the roof beam. That covers crew cab trucks, kayak racks, and roof-top cargo boxes without scraping.
Choose a Style That Matches Your Climate
- Flat-roof carport: Cheapest, fastest, works in low-snow zones (under 20 psf snow load)
- Shed roof (single slope): Sheds snow, simple framing, attaches well to a house
- Gable roof: Strongest for heavy snow loads, classic look, more lumber
- Lean-to: Attaches directly to an existing wall, saves cost on two posts
Check your local building department for ground snow load. Anything over 30 psf demands either a shed or gable roof — flat carports collapse in heavy snow no matter how big the lumber.
Sample Plan: 12 by 20 Shed Roof Carport
This is the design I have built more than any other. It clears one full-size truck, sheds snow, costs about $1,650 to $1,950 in 2026 lumber prices, and meets code in most US counties with a simple permit.
- Posts: 6 six-by-six pressure-treated, 10 feet tall, set 3 feet deep in concrete piers (Sonotube or footings to local frost depth)
- Front beam: Double 2×10 spliced over posts
- Rear beam: Double 2×8 (lower side of the slope)
- Rafters: 2×8 at 24 inches on center, spanning 12 feet with a 4-in-12 pitch
- Roof sheathing: 5/8 inch CDX plywood, or metal roof panels direct to purlins
- Roof covering: 26-gauge ribbed metal panels with neoprene-washer screws
Foundation Decisions That Make or Break the Build
Posts on concrete piers below frost line are the durable standard. In Minnesota or Maine, that is 48 inches. In Tennessee, 18 inches works. Surface-mounted post bases on a slab look quick but lift in heavy wind unless anchored with hold-downs sized to the local wind speed.
If you are pouring a slab to park on, do it before the carport posts. Use 4-inch thick 3,500 psi concrete with a 6-mil vapor barrier underneath and #4 rebar on a 24-inch grid. Slab on grade gives you a clean floor and helps anchor the structure once you bolt the posts to embedded brackets.
Permitting and Setbacks
Most jurisdictions require a permit for any roofed structure over 120 to 200 square feet. Permit fees run $80 to $250. You will likely need to show a site plan, a foundation detail, framing details with lumber sizes, and a signed setback compliance form. Lean-to designs attached to a house always need a permit because they alter the existing structure.
Setbacks vary widely. Five feet from the side property line is common; some counties require ten. Check before you set posts — moving a finished carport is a $4,000 mistake.
Tools and Crew
You need a circular saw, impact driver, six-foot level, post hole digger or rented auger, mixing tub, framing square, and a 16- or 20-foot extension ladder. A second person is non-negotiable when setting beams; a third makes the roof go faster. Plan 18 to 24 labor hours across two weekends with a helper.
Rent a one-person auger ($95 a day) instead of digging six holes by hand. Your back will thank you and the depth will be consistent across all six piers.
Hardware That Earns Its Cost
Use Simpson Strong-Tie ABU66 post bases ($28 each) over cast-in-place anchor bolts. They lift the post 1.5 inches off the concrete to prevent rot at the base. Spec Simpson H2.5A hurricane ties at every rafter-to-beam connection. In high-wind zones, upgrade to H10A or LSTA21 straps. Hardware is two percent of the budget and the entire reason your carport stays standing.
Finishing Touches
Add gutters and downspouts before winter — even an open carport sheds enough rain to wash out the gravel beside it in one season. Paint or stain pressure-treated lumber after it dries (typically four to eight weeks). Solar-powered shed lights mount easily to the rafters and pay for themselves the first time you unload groceries at night.
What Skipping the Plans Costs
Eyeball-built carports fail in three predictable ways: undersized rafters sagging under snow, posts heaving from shallow footings, and roofs lifting in wind because hurricane ties were skipped. Each failure averages $1,500 to $4,000 in repairs or full rebuilds. Spend the four hours up front on proper plans, span tables, and a permit, and you will get a structure that outlives two cars.
