---
title: "How to Build a Pole Barn: Posts, Girts, Trusses and the Permit"
description: "How to build a pole barn step by step, using the post depths, spacing and framing two counties publish for non-engineered barns, plus the permit and the inspections."
url: https://yespermit.com/how-to-build-a-pole-barn/
updated: 2026-10-13
language: en-US
---

# How to build a pole barn

A pole barn stands on treated wood posts set in concrete-filled holes instead of a continuous foundation. You set the posts, nail girts across them for the walls, bolt engineered trusses on top, add purlins and screw on metal roofing and siding. Snohomish County, Washington, for example, asks for holes 48 inches deep and 24 inches wide on its non-engineered design.

*Updated October 13, 2026. Every regulatory fact below links to its official source.*

## Key facts

- A pole building is a wooden structure supported by wooden posts in concrete footings instead of a continuous foundation wall, and its walls are framed with horizontal members rather than vertical studs.[^1]
- Laramie County's guide is written for the 2021 International codes.[^2]
- The International Residential Code only exempts one-story detached accessory structures up to 200 square feet of floor area, and both Waterford Township, Michigan, and Johnson County, Kansas, use that 200 square foot line.[^7][^5][^6]
- Contact 811, or your state 811 center's website, a few business days before you dig, so buried utilities are marked with paint or flags.[^4]
- Armada Township, Michigan, lists the post hole or footing inspection as the first inspection for pole barns.[^3]

**We handle the permit. You build.** All-in, until approved: $399 (Fall 2026 launch price, valid through November 30, 2026; regular price $499), approved or your money back ([conditions](https://yespermit.com/guarantee/)): [order](https://yespermit.com/all-in/). Prefer to file it yourself? [Permit Kit](https://yespermit.com/permit-kit/), $349.

## What a pole barn is, and why it is fast to build

A pole building is a wooden structure supported by wooden posts in concrete footings instead of a continuous foundation wall, and its walls are framed with horizontal members rather than vertical studs[^1]. That is what makes it quick and cheap: no foundation wall to form and pour, few pieces, and metal skins that go up in long sheets.

The method is simple, but the numbers are not yours to choose. Post depth, post size, spacing, girt and purlin size all come from a design, either an engineer's or a prescriptive one published by your county. This guide uses the two county designs below as worked examples. Use your own county's figures for your barn.

## Two published designs, side by side

Snohomish County, Washington, and Laramie County, Wyoming, both publish a pole barn you can build without engineering, provided you stay inside every limit[^1][^2]:

| | Snohomish County, Washington | Laramie County, Wyoming |
| --- | --- | --- |
| Maximum size | 24 ft wide, 36 ft long | 40 ft wide, 60 ft long, 2,400 sq ft |
| Maximum wall height | 12 ft eave | 14 ft |
| Posts | 6x6 treated at corners and end walls, 6x8 treated mid-span | 6x6, or three 2x6 laminated, treated below ground |
| Post spacing | 12 ft on center, max | 8 ft on center, max |
| Holes | 48 in deep, 24 in diameter, 6 in punch pad, concrete backfill | Caisson 48 in deep, 18 in wide up to 32 ft building width, 24 in wide from 32 to 40 ft |
| Wall girts | 2x6 at 24 in vertical spacing, bottom girt 2x10 treated | 2x6 minimum at 30 in max, treated grade board 2x6 minimum |
| Purlins | 2x6 at 24 in on center | depend on truss spacing, at 24 in on center |
| Trusses | 24 ft span max, 25 lb snow load, engineering for trusses | by a Wyoming licensed engineer, stamped plans on site |
| Roof and walls | not specified | 29 gauge steel, minimum |

Snohomish County designed its version for a 25 pound snow load, 110 mph wind and seismic zone D2, and says the building can go smaller but not bigger than the design[^1]. Laramie County's guide is written for the 2021 International codes[^2]. Those design loads are local, which is why you cannot borrow another county's design for your own lot.

## Do you need a permit to build a pole barn?

Almost always. The International Residential Code only exempts one-story detached accessory structures up to 200 square feet of floor area[^7], and both Waterford Township, Michigan, and Johnson County, Kansas, use that 200 square foot line[^5][^6]. Check the permit before you buy the kit: our [pole barn permit guide](https://yespermit.com/pole-barn-permit/) covers the farm exemption, the drawings and the fees.

## Step by step

### 1. Check the permit and the rules

Before anything else, find out three things: whether you need a building permit, which setbacks apply on your lot, and whether your county publishes a non-engineered design. Waterford Township, for example, requires a detached accessory building to sit in the rear yard, at least 5 feet from the rear and side property lines, measured to the closest point including the overhangs[^5]. Overhangs count, so draw them on the site plan.

### 2. Call 811 and stake out the building

Contact 811, or your state 811 center's website, a few business days before you dig, so buried utilities are marked with paint or flags[^4]. Then stake the four corners, check that the diagonals are equal so the building is square, and measure to the property lines again with the overhang added.

### 3. Dig the holes and set the posts

Dig each hole to the depth and width of your design. On the Snohomish design that is 48 inches deep and 24 inches across, with a 6-inch concrete punch pad under each post and concrete backfill[^1]. Use posts rated for ground contact: Snohomish calls for pressure-treated posts at .60 retention, and Laramie for posts treated below ground[^1][^2].

Set the corner posts first, brace them plumb in two directions, then run a string line between them to align the posts in between. Do not backfill yet: Armada Township, Michigan, lists the post hole or footing inspection as the first inspection for pole barns[^3].

### 4. Install the grade board and wall girts

The grade board, also called a skirt board or splash plank, is the bottom horizontal member, in contact with the ground, so it must be treated: Snohomish asks for a treated 2x10 bottom girt, and Laramie for a treated 2x6 minimum[^1][^2]. Above it, girts run horizontally between posts. Snohomish face-nails each girt to the post with four galvanized 16d nails[^1].

### 5. Set the trusses

Trusses are the one part you never size yourself. Snohomish County requires engineering for the trusses, and Laramie County requires trusses by a licensed engineer with the stamped plans on site for inspections[^1][^2]. Order them with your county's snow load in hand.

On the Snohomish design, each truss is fastened to its post with five 4 1/2 inch structural screws or a 7/8 inch bolt, with 18-inch shear blocks matched to the post size and bolted with 3/4 inch galvanized bolts[^1]. Raise the trusses with enough help or a lift, and brace each one before you let go of it.

### 6. Add purlins and bracing

Purlins run across the trusses and carry the roof sheets. Snohomish uses 2x6 purlins at 24 inches on center, lapped at least 24 inches[^1]. Laramie sizes them by truss spacing, from 2x4 laid flat for trusses 4 feet apart to 2x6 on hangers for trusses 8 feet apart, always at 24 inches on center[^2]. Laramie also details 2x6 corner braces secured at the post and at each girt[^2].

### 7. Pass the rough inspection, then roof and side it

Armada Township inspects the framing before the metal is installed[^3]. Book it before the roofing crew arrives. Then screw on the roof and wall sheets.

### 8. Pour the floor and call for the final

A concrete floor is optional on the Snohomish design, at 4 inches thick[^1]. Install the doors, finish any electrical work under its own permit, and schedule the final. In Armada, the final building inspection can only be scheduled once the plumbing, electrical and mechanical inspections are complete[^3].

## Mistakes that cost a barn

- **Going one foot bigger than the design.** The prescriptive designs are maximums. Snohomish says the building can go smaller but cannot increase from the design shown[^1], and Laramie requires a licensed engineer once a barn falls outside its guide[^2].
- **Turning the barn into a home.** A standard pole barn serving as a barn or storage shelter is designed as Risk Category I, while a residence is Risk Category II, so Snohomish requires additional engineering to make it safe to live in[^1]. Laramie County warns that foundation, fire separation, plumbing and roof issues appear when owners remodel these buildings for living, and that land-use rules may prohibit a second residence[^2].
- **Adding a loft.** A mezzanine or second story needs engineered plans in Snohomish County[^1].
- **Skipping the hole inspection.** Once the concrete is in, the inspector cannot see the depth. Armada charges $175 plus a $75 inspection fee when work starts before the permit is issued[^3].
- **Forgetting the post-frame rule.** In Johnson County, Kansas, a post-frame building must be designed by a Kansas-registered design professional[^6], so a kit's generic drawings are not enough there.

## Before you dig: the permit

Everything above starts after the permit is issued. The application wants a site plan with the distances to your property lines, drawings that match your county's design or your kit, and sometimes a use form. That is the file our Permit Kit prepares for your address, from your county's own rules. The All-in offer adds the review before filing and follows every county comment until the permit is approved.

## Common questions

### How deep do pole barn posts go?

It depends on your county and on the building. Snohomish County, Washington, sets posts 48 inches deep in 24-inch holes on a 6-inch punch pad with concrete backfill. Laramie County, Wyoming, uses caissons 48 inches deep and 18 inches wide for buildings up to 32 feet wide, or 24 inches wide for buildings 32 to 40 feet wide.

### How far apart are the posts on a pole barn?

Snohomish County allows up to 12 feet on center on its non-engineered design, with a maximum building of 24 by 36 feet. Laramie County allows up to 8 feet on center for buildings up to 40 by 60 feet. Wider spacing or bigger buildings need an engineered design.

### Can I build a pole barn without an engineer?

Sometimes. Some counties publish a prescriptive design you can follow without engineering, within limits on size, height and post spacing. The trusses still come with engineering from the truss maker, and a pole barn meant as a home, or with a second floor, needs an engineered design.

### Can I live in a pole barn?

Not as a standard barn. Snohomish County designs a barn or storage shelter as Risk Category I, low risk because it is normally unoccupied, while a residence is Risk Category II, so additional engineering is required. Laramie County warns that foundation, fire separation, plumbing and roof issues appear when barns are remodeled into homes.

## Get it done

**We handle the permit. You build.** All-in, until approved: $399 (Fall 2026 launch price, valid through November 30, 2026; regular price $499), approved or your money back ([conditions](https://yespermit.com/guarantee/)): [order](https://yespermit.com/all-in/). Prefer to file it yourself? [Permit Kit](https://yespermit.com/permit-kit/), $349.

## Sources

[^1]: [Snohomish County, Washington, Planning and Development Services, Assistance Bulletin 113, Pole Buildings (revised September 2025)](https://snohomishcountywa.gov/DocumentCenter/View/53667/), checked October 13, 2026.
[^2]: [Laramie County, Wyoming, Planning and Development, Pole Barn Construction Guide](https://laramiecountywy.gov/files/sharedassets/public/v/1/planning/documents/building/handout_pole-barn-construction-guide.pdf), checked October 13, 2026.
[^3]: [Armada Township, Michigan, Building application requirements for accessory buildings (March 2025)](https://armadatwp.gov/wp-content/uploads/2026/07/Accessory-bldg.-requirements-2026.pdf), checked October 13, 2026.
[^4]: [811, Before you dig (national call-before-you-dig service)](https://call811.com/), checked October 13, 2026.
[^5]: [Waterford Township, Michigan, Building permit requirements, residential accessory buildings and structures (updated 07/22/2026)](https://waterfordmi.gov/DocumentCenter/View/9983/Building-Permit-Requirements---Accessory-Structure-), checked October 13, 2026.
[^6]: [Johnson County, Kansas, Building Codes, Accessory and agriculture building permits](https://jocogov.org/department/building-codes/building-permits/accessory-and-agriculture-building), checked October 13, 2026.
[^7]: [City of Federal Way, Washington, Residential permit exemptions (International Residential Code, Section R105.2)](https://www.federalwaywa.gov/page/residential-permit-exemptions), checked October 13, 2026.

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