Start with the step-by-step guide to building a pole barn, then price it and set the frame. Every count and size comes from the barn designer for a real 30x40, so the guides and your plan always agree.
Start here · 13 min read
The order a pole barn goes up in, the numbers each step needs and what to confirm before the next one, taken from the build order in our plans and the county post-frame guides behind them.
Read the guideFor the 30x40 pole barn at 30 psf of ground snow, 115 mph of wind and a 36 in frost line, as the designer draws it. Our default: the number the barn designer draws. Guide rule: from the county post-frame guides or the Post-Frame Building Handbook. Depends: your county, your loads or your store change it. Your building department and the truss maker's engineer have the last word.
After the build guide, price the barn and set the frame. Every drawing is the 30x40 from the free plans, as the designer draws it.
Step 1
Every free design priced line by line, the slab and a hired crew on top, and the four choices that move the total.
Step 2
Truss spacing is post spacing: how far apart they go, and what the bay does to the purlins, girts and posts.
Step 3
What a shell and loft plan covers, and what a home inside needs on top: the engineer, the foundation, egress, fire separation and the permit.
Each links straight to its answer, with the sources beside it.
Calculators
Pole barn cost calculator$14,100materials for the 30x40 pole barn, 43 lines at dated store prices and sourced estimatesPick the width, length, eave and floor, get the designer's full materials list, and add the published labor range if you hire the shell out.Price your barn
Post spacing and depth calculatorHow many posts, what size, how far apart and how deep, with the footing pads and the bags of concrete.19 posts6x6 post, 4' deep
Purlin and girt spacing calculatorPurlin size and spacing for your truss spacing and snow load, and the girts for the walls.2x6 at 24 inon 8' bays at 30 psf
Barn designerEvery number above, for the barn you draw: posts, trusses, purlins, the checks and the priced materials list. Free, no account.12 of 12planner checks passed on the 30x40Post-frame guides from county building departments, the Post-Frame Building Handbook (NRAES-1) and the National Frame Building Association come first. Price guides are marked as secondary and used only for costs no store lists.
Post counts, depths, truss counts, purlin sizes and prices come from the barn designer's plan for a real size, the same engine that draws the free plans.
Every price names its store or price guide and the day we read it. Trusses and slab concrete are estimates from published ranges, kept apart. How the checks work
Design it, then build it
Draw your barn in 3D for your snow, wind and frost line. The posts, the trusses, the purlins and the priced materials list follow every change. Free, no account.
Design my barn, free
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