Idaho Falls Shop BuildersIdaho Falls, ID · post-frame & pole barns

Questions · Eastern Idaho

Eastern Idaho Shop Building Questions

These come up on nearly every shop project in this valley. Each answer is built from a published source, and the ones with no published source say so outright.

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Ask the question straight out. Whatever the published sources say about it comes back to you, with a note where nothing is published.

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On this page

Load and engineering

The design load is decided once, at the drawing stage, and it is not cheap to revisit.

What snow load do I have to design for?
Whatever your permitting jurisdiction has adopted, which is not always the newest research figure. The City of Idaho Falls requires a 47 psf ground snow load, a number that traces to the 1986 edition, while the 2015 University of Idaho study calculated 23 psf for the same location. The adopted figure governs. Unincorporated Bingham County publishes a formula instead, in Bingham County Code Title 8, §8-1-2-1: ground snow load = (elevation ÷ 100) − 5. Blackfoot at 4,498 feet: 4,498 ÷ 100 = 44.98, minus 5 = 40 psf, where the 2015 study calculated 28 psf — the adopted number is the higher one there too. Confirm the number with the office that will stamp your plans before ordering trusses.
Why does the next town over have a different number?
Elevation is one input to the model, not the whole of it. In the 2015 study Iona sits at 4,783 feet with 23 psf while Roberts sits at 4,777 feet with 33 psf — six feet apart vertically, ten pounds per square foot apart on paper. Ririe carries 59 psf and Ammon 24. Terrain, exposure and the station data behind each point all move the result, so a truss package priced off a neighbouring town's figure is priced off the wrong figure.
How deep do the posts have to go?
The City of Idaho Falls publishes a 30-inch frost line, and Bingham County lists a 30-inch frost depth. Jefferson County Ordinance 2017-01 amends IRC Table 301.2(1) to a 30-inch frost depth with a −4°F winter design temperature; that came from a scanned document, so confirm it with the county at (208) 745-9220. Bearing conditions can require going deeper than frost depth, which is a soils question rather than a code minimum.
What happens if the excavation hits rock?
It happens across the Snake River Plain, where loess sits over basalt at shallow depth. No source publishes a dollar figure for a basalt excavation premium here, so anyone quoting you one is quoting their own rate, not a market rate. Rock work sits inside the published $3,000 to $20,000 or more site-prep range. Get the rock contingency written into the bid before excavation starts rather than settled after.

Permits and the ag exemption

Seven offices issue permits across this area, and the exemption is narrower than the shorthand suggests.

Do I need a permit for an ag building?
Idaho Code §39-4105 exempts farm buildings from the state building code, but that does not clear local zoning. Bonneville County Code §156.086 requires a zoning permit for any structure valued at $100 or more when completed, and setbacks still apply. Under §156.040 the parcel must be an agricultural unit of 5 acres or more, the structure must house farm implements, hay, grain, poultry or livestock, and the owner signs a compliance statement.
Can I live in a pole barn in Idaho?
Not one built under the agricultural exemption. Bonneville County Code §156.040 requires that an exempt structure not be used for human habitation, as a place of employment for processing, or for public use. Converting one later takes a conversion permit, full compliance with current code, and an occupancy permit — current code, not the code in force when it was built. If living space is anywhere in the plan, design and permit it on the residential path from the outset.
Who issues my permit?
Whichever office has authority over the ground the building will stand on — the postal address is irrelevant to it. Idaho Falls has its own Building Division at (208) 612-8270. Unincorporated Bonneville County goes to Planning & Zoning at (208) 524-7920, Ammon to its city department at (208) 612-4024, Shelley to City Building & Safety at (208) 681-3391, Blackfoot city to (208) 812-4198, unincorporated Bingham County to (208) 782-3177. Rigby, Lewisville, Menan and unincorporated Jefferson County all go to Jefferson County at (208) 745-9220.

What it costs

Market ranges with named sources. Not one of these figures has been priced against your building.

How much does a 40x60 shop cost here?
Steel Structures America publishes a $119,721 median across 140 completed 40x60 projects, across Idaho, Washington, Oregon, Colorado and Montana. That is regional data, not an Idaho Falls quote. Shell-only for the same footprint runs roughly $36,000 to $67,000. Trusst Buildings of Shelley publishes $30 to $60 per square foot for finished work, which on 2,400 square feet spans $72,000 to $144,000. Where your project lands inside that spread depends on slab, doors, insulation, site prep and the snow load your jurisdiction adopts.
Why is the kit price so much lower than the bid?
Because they are answers to different questions. A materials package is $8 to $18 per square foot — lumber, steel and fasteners delivered to the site. A shell erected with no slab is $15 to $28. A basic functional shop with slab, a door and power is $22 to $42. A finished shop is $30 to $60. An advertised kit price and a contractor's bid can both be honest and still differ by four times, because one stops at the pallet.
What does the concrete add?
A 4-inch slab with wire mesh runs $12,000 to $20,000 on a 40x60. Site prep and excavation on top of that is published at $3,000 to $20,000 or more, depending on how much cut, fill, gravel and access work the parcel needs. Those two lines together are commonly the largest single jump between a shell price and a usable shop, and they are also the pair most sensitive to what the ground turns out to be.
Can I get a ballpark before a site visit?
You can get a range, and the ranges on this site are the honest ones. What a phone call cannot settle is the parcel-specific part: access, cut and fill, how deep the rock sits, and which jurisdiction's design criteria apply. Those variables are the difference between a $70,000 building and a $140,000 one. Use the published ranges to decide whether the project is in budget at all, then get a real number on your actual address.

Getting it built

Where a timeline figure is not published, this page says so rather than estimating it.

How long does a build take?
Review times are not published by any office on this list, and inventing one would be worse than useless to somebody planning around it. The sequence is knowable even when the durations are not: design and engineered stamped plans, which run $1,500 to $5,000, then permitting, then site prep, then the shell, then slab and finish work. Ask the permitting office for its current turnaround when you file, and ask any builder bidding the work for their current lead time in writing.
What is the realistic lead time to be closed in before winter?
The constraint is frozen ground, not the calendar. Footings here go to 30 inches, and neither excavation nor concrete tolerates frost — so the site-prep and slab stages define the whole schedule. Design, engineered plans and permit review all have to be finished and sitting on the shelf before that window opens. Since none of the offices publish a review time, the only part you control is how early the drawings are started.

Go deeper

Ground snow load by town →

The full table, the binding-number rule and the Bingham formula.

What a shop costs →

The per-square-foot ladder, completed medians and a cost-driver table.

Permits and the ag exemption →

Who issues what, §39-4105 in full, and the habitation trap.

Something here we haven't covered?

Put the question in the box with your parcel address. If a published source answers it you will get the source; if nothing is published, you will be told that plainly instead.

Call (208) 441-0630

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