How to Assemble a DIY Carport Kit

What a DIY Carport Kit Includes

A DIY carport kit is a boxed set of pre-cut, pre-drilled frame members, roof sheets, hardware and instructions, while the pad, the permit, the tools and a helper stay with the buyer. Sellers also call it a do-it-yourself carport kit, and the pad is the level slab or footings the frame sits on.

The finished structure is a carport, a roofed, open-sided shelter for vehicles. For the definition, read what a carport is. Table T1 shows who supplies each item and which seller says so.

Some kits are frame-only or roof-only; read the seller's parts list. Alan's says "pour your own foundation". Last verified 2026-10-06; sources: Viking kit page, Carport.com DIY kits, Lyon DIY vertical kit guide, Alan's kit page.

Carport.com lists 14-gauge American steel frames as standard, with a 12-gauge upgrade, and 29-gauge sheeting. Gauge is the thickness of steel.

For a side-by-side look at named sellers, see carport kits compared.

Check the Rating, Permit and Utilities Before You Order

Check three things before ordering a DIY carport kit: what the maker states about wind and snow, whether the local office wants a permit, and where the underground lines run.

Of six kit sellers read, only ShelterLogic prints a wind and snow figure on its kit page: 100 mph and 35 psf, for a standalone carport with proper anchoring per local code. The unit psf means pounds per square foot.

Read each row of Table T4 with how a carport maker and a seller differ in mind: a figure belongs to the company that prints it.

Every row is a seller's statement, printed with the seller named. ShelterLogic states its figure for a standalone carport with proper anchoring per local code. Alan's prints a 150 mph and 35 psf standard on its building pages, which describe dealer-installed buildings; the kit page prints no figure. Last verified 2026-10-06.

This guide gives general information, not engineering, legal or contracting advice. Follow your kit maker's instructions and drawings, and ask a licensed professional about site conditions, anchors and loads.

A 12x20 kit covers 240 square feet and a 20x20 covers 400, both above the 200 square foot baseline in the International Residential Code, so the carport permit rules decide whether you can put one up. Building departments regulate the finished structure, not the method, so a kit follows the same permit rules as a site-built structure of the same size, says Viking. Local lines differ. Confirm current requirements with your local building department before beginning construction.

Call 811 a few business days before you dig; the service is free. 811 is the national call-before-you-dig number.

Kit makers set anchors with the base rails. Lyon puts rebar about 3 feet long through the base rails in step one of its guide, so this page checks the anchors twice, in step 3 and again in step 7.

How to Assemble a Carport Kit, Step by Step

Assemble a DIY carport kit in seven steps: check the site, prepare the pad, set the base and anchors, raise the frame, brace it, fit the roof and check every fastener. For the metal-only version, read how to install a metal carport kit.

Seller guides rate the work differently: Alan's lists its seven-step guide as "Advanced" with a total time of "1+ day", and JLC puts the concrete cure at 28 days.

1. Check the Permit, Utilities and Site

   Check the permit, call 811 and mark the site before ordering or digging.

   Ask the local building office whether a kit of your size needs a permit. The International Residential Code baseline is 200 square feet, so a 12x20 (240) and a 20x20 (400) sit above it. Building departments regulate the finished structure, not how you assemble it, says Viking. Call 811 a few business days before you dig; the service is free. Clear the site and compare it with the kit drawing.

2. Prepare the Pad and Footings

   Prepare the pad: dig footings or pour a slab, then let the concrete cure.

   Mark the footings or slab from the kit drawing. Dig the holes to the depth the drawing and your frost line call for, or form the slab. Pour the concrete, using Table T7 to size the order. Ask the maker for its minimum cure time before you load the anchors. JLC says 3,000-psi concrete reaches rated strength in 28 days.

   Table T7. Concrete to order for the pad, in cubic yards

   Pad	Concrete (cubic yards)
   Six 12x36 in footings	Concrete (cubic yards)0.52
   Eight 12x36 in footings	Concrete (cubic yards)0.70
   12x20 slab, 4 in thick	Concrete (cubic yards)2.96
   20x20 slab, 4 in thick	Concrete (cubic yards)4.94
   20x20 slab, 6 in thick	Concrete (cubic yards)7.41

   Geometry only: a footing is a cylinder 12 inches wide and 36 inches deep (0.785 cubic feet per foot of depth times 3), a slab is length times width times thickness, 27 cubic feet to the cubic yard, no waste allowance. The kit drawing governs the footing size and count. The number of bags depends on the yield printed on the bag. Last verified 2026-10-06.

   A 20x20 slab at 4 inches needs 4.94 cubic yards.

3. Set the Base Rails or Posts and Anchors

   Set the base rails or posts and fasten them to the anchors.

   Lay the base rails on the pad and square them to the drawing. Fasten the rails with the rebar or anchor bolts the kit lists. Lyon sets its rebar anchors, about 3 feet long, through the base rails in its first step. Use the anchor count and type on your drawing.

   

4. Assemble and Raise the Frame

   Assemble the frame on the ground, then raise it with a helper.

   This guide gives general information, not engineering, legal or contracting advice. Follow your kit maker's instructions and drawings, and ask a licensed professional about site conditions, anchors and loads.

   Bolt the trusses or legs together on the ground with the supplied hardware. Raise each frame with a helper and fasten it to the base rails. Viking lists a helper and basic tools for its kit. Follow the order in your instructions.

5. Brace and Square the Frame

   Brace the frame and check that it is square and plumb.

   Fit the bracing the drawing shows. Measure both diagonals of the frame; equal diagonals mean it is square. Check each leg with a level. Lyon sets bracing twice, once before the frame stands and once after.

6. Fit the Purlins and Roof Sheets

   Fit the purlins, then screw on the roof sheets and trim.

   Fasten the purlins across the frame at the spacing the drawing gives. Lay the roof sheets from one end, overlapping as the instructions show. Screw each sheet with the supplied screws. Add the eave and ridge trim last, as Lyon does.

7. Check the Anchors, Trim and Fasteners

   Tighten every anchor, bolt and screw, then walk the frame once more.

   Return to each anchor and confirm it is tight. Check every bolt, screw and trim piece against the parts list. Look for gaps or loose edges in the roof sheets. If you pulled a permit, book the inspection.

DIY Carport Kit Questions