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Free starting design ยท Carport

20x20 carport

400 sq ft, 9' eave, 4/12 steel roof.

12 of 12 planner checks passed
The 20x20 carport, drawn by the barn designerThe 20x20 carport with its width, length, eave and peak heightThe frame of the 20x20 carport: posts, girts, trusses and purlins, without the steelInside the 20x20 carport, the near walls and roof cut away
Drawn by the designer from this plan
Customize this design, free

Preliminary checks for 30 psf ground snow, 115 mph wind, 36 in frost line. Local approval not checked.

Footprint
20x20 ft
Posts
6 x 3-ply 2x6 post, nail-laminated, treated UC4B
Trusses
3 at 10'
Doors
none, open on all sides

About $3,200 in materials, before sales tax, delivery and tools.

Building it? The $39 builder's plan dimensions every post, girt and truss. See sample sheets

Planner checks

Preliminary checks passed for the loads you entered. Local approval not checked.

Each bar is how much of its bending or deflection limit a purlin or door header uses at 30 psf of snow. We stop at 95%: past that, purlins move closer or go up a size and a header goes to the next size.

  • Roof purlins90% of 95% allowed2x6 on edge, 24 in o.c., 10' span; bending governs

what this design uses room to spare

Green passes the rule or the calculation we checked against, amber asks you to look at something before you build, red fails it. These are preliminary checks for the loads you entered, not a structural approval. The truss design comes from the truss manufacturer you order from, often with an engineer's seal (ask for it where your building department needs one); a qualified professional designs the footings when your soil or your building department calls for it; your local building authority sets the loads, reviews and approves.

Specification

The 20x20 carport, part by part.

The carport

Footprint
20x20 ft, 400 sq ft
Eave
9'
Roof
4/12 steel
Doors
none, open on all sides

The frame

Posts
6 x 3-ply 2x6 post, nail-laminated, treated UC4B
Post depth
4' on 18 in pads
Trusses
3, 20' span
Purlins
2x6

Cost and time

What it takes to build.

Materials, about (rounded estimate, before sales tax, delivery, labor and site work)$3,200

  • Lumber$906.90
  • Trussesest. $510.00
  • Steel and trim$1,077.27
  • Hardware$299.09
  • Site$441.60

Shelf prices from Home Depot, Summertown Metals, Lowe's and Best Buy Metals online store, read Sep 30, 2026 to Oct 13, 2026. Trusses and concrete estimated from published ranges. Before sales tax, delivery, labor and site work.

At shelf prices
$2,477.36
Trusses and concrete, estimated
$757.50
Exact sum
$3,234.86
Per sq ft of floor
$8.09
Build time
40 to 60 h
a crew of two, about 3 to 4 working days; a broad reference, not a schedule
Labor if hired, broad reference
$2,000 to $6,000
Separate from the materials.

Prices differ by store and by week: size your own barn in the pole barn cost calculator, which runs the same numbers.

Free and paid, side by side

Design it free. Build it from the $39 plan.

Free

On this page and in the designer, no account

  • This design in 3D, and every change you make to it
  • Every planner check, with its rule and source
Cost estimate
About $3,200 in materials, line by line, on this page. See the estimate
Summary PDF
The design, its checks and its materials list on a few pages. A summary, not the build drawings.
Customize this design, free

$39 once

The drawings you build from, for the design you finish. About 19 to 25 Letter sheets, 23 for the 30x40 pole barn.

  • The post layout, every post dimensioned from one corner
  • Every wall framed: girts, headers and openings with heights
  • The truss order sheet to hand the truss maker
  • The roof frame and the steel, panel by panel
  • The cut list, the shopping list with store prices and the build, step by step
Get the $39 plan for this design

You check out in the designer, with this design loaded. If the plan has an error, we fix it or refund you within 30 days. Guarantee terms.

Real sheets from the 23-sheet sample plan for the 30x40 pole barn

The sample was printed on an earlier date, so its prices can differ from the estimate above. Your plan prints the same prices as the estimate.

  • Sample sheet 1 of 23: post layout

    Post layout

  • Sample sheet 2 of 23: wall framing

    Wall framing

  • Sample sheet 5 of 23: truss order sheet

    Truss order sheet

  • Sample sheet 4 of 23: shopping list

    Shopping list

Build phases

From the first hole to the last panel in 5 phases.

About 40 to 60 hours for a crew of two, about 3 to 4 working days; a broad reference, not a schedule. Each picture is this design at the end of its phase, drawn by the designer, with that phase's new parts in blue.

  1. The 20x20 carport after phase 1: holes, pads and posts

    01

    Holes, pads and posts

    Stake the corners, dig 6 holes 18 in across to 4' 9", pour the pads, then set every post plumb on a string line and pour the collars.

  2. The 20x20 carport after phase 2: eave girts

    02

    Eave girts

    Mark the eave on every post from one reference, cut the tops and bolt the eave girt pairs.

  3. The 20x20 carport after phase 3: trusses and knee braces

    03

    Trusses and knee braces

    Lift the trusses onto the posts, bolt them with the maker's temporary bracing, then bolt the knee braces from post to girt and truss.

  4. The 20x20 carport after phase 4: purlins

    04

    Purlins

    Run the 2x6 purlins on edge with a tie at every truss, then the bottom chord bracing.

  5. The 20x20 carport after phase 5: roof steel

    05

    Roof steel

    Start at the end away from the storm wind, square the first panel to the eave and screw on the supplier's pattern.

This is the summary. The $39 builder's plan breaks these phases into a build order with the new parts highlighted, a how-to detail and a check at each step.

The guide to building a pole barn walks through each phase in general terms.

Questions

Anything else? Write to us or read the questions about all plans.

Questions about the 20x20 plan

For this 20x20 design the materials come to about $3,200: $2,477.36 at shelf prices plus $757.50 estimated from published ranges for the trusses and the concrete, before sales tax, delivery, labor and site work. If you hire the build out, published price guides give a broad range of $2,000 to $6,000 on top, a reference rather than a quote. Every line, with its store and date, is in the materials list on this page.

It depends on your town or county, not on the plan. Many building departments ask for a permit for any roofed structure over a set size, and setbacks apply either way. Ask yours before you dig, with this design's size (20x20 ft) and post layout in hand.

In this design the posts go 6' into the ground on 9 in pads 18 in across, deeper than the 4' we use on a closed building, because an open structure has no walls to share the wind. The depth also stays below the 36 in frost line you entered.

3 trusses at 10' on center, one on each post line, for a 20' span. The truss manufacturer designs them for your loads, often with an engineer's seal (ask for it if your building department needs one); the plan's truss order sheet lists what to give them.

About 40 to 60 labor hours, roughly 3 to 4 working days for a crew of two. It is an estimate from the parts count, not a schedule: weather, the site and the delivery of the trusses move it.

It depends on where you build. Many counties exempt agricultural buildings, many do not, and almost all ask for a permit for a garage or anything you will live in. The planner does not check local rules: ask your building department before you dig.

Sizes to compare

All 19 free pole barn plans

Your loads, your barn

Make the 20x20 yours.

Change the width, the length, the bays, the eave, the doors and your loads. The post size and depth, the purlins, the headers and the materials list follow every change. Free, no account.

Customize this design, free
Designing
Free
Builder's plan
$39 once
Account
Not needed
Inside a new pole barn: trusses, girts and a workbench, the overhead door open on a fieldIllustration