Barndominiums & post-frame
Building a barndominium in St. Anthony, Idaho
Published · every figure below was checked against its primary source on the date shown.
The lane nobody local has claimed
Drive the valley floor around St. Anthony and you will see them: metal-clad buildings with a shop at one end and a house at the other, or a full residence under a post-frame roof. It is a normal way to build here. It suits the ground, it suits people who need to keep equipment indoors, and it suits a budget that would rather buy square footage than trim.
What you will not find is a local builder who has planted a flag on it. The companies advertising post-frame homes into this valley are largely statewide operators marketing in from hundreds of miles away, and their pages are written for the whole state. None of them mentions the Fremont County rule below, because a page written for forty counties cannot.
The rule that catches most designs
Buried in the county's pre-construction checklist, printed in capitals inside the application block rather than in the body text, is this:
“***ALL FREE-STANDING POST & BEAM STRUCTURES REQUIRE ENGINEERED STAMPED PLANS.***”
— Fremont County, Pre-Construction Check List for Building Permits, rev. 17 April 2026, printed in the application block. Retrieved 14 August 2026
Read what it does not say. There is no square-footage threshold. No snow-load condition. No exemption for a small building or an unheated one. Free-standing post and beam structures require engineered stamped plans, full stop.
That is the single most expensive surprise available to somebody planning a post-frame build here, because the whole appeal of the method is speed and simplicity, and a stamped engineering package is neither. Budget for it from the first conversation and it is a known cost. Discover it at submittal and it is a delay on top of a cost.
There is a real distinction worth being precise about. Not every building that looks like a barndominium is post and beam. Plenty are conventionally framed on a slab with metal cladding over the top, and those are not what that sentence describes. The construction method decides whether the rule applies, not the styling. Settle the method before you buy plans.
Height: which cap applies to you
The county states two limits, and which one you get depends on what the building legally is rather than what it contains.
| What the building is | Maximum height | Why it matters for a barndominium |
|---|---|---|
| A building (the dwelling) | 30 feet | Enough for a tall shop bay with finished space above, in most designs. |
| An accessory structure | 25 feet | Five feet less. A detached shop you later want to live in starts life in the tighter category. |
The trap is sequencing. People often build the shop first, live elsewhere, and finish the living space later. If the shop went up as an accessory structure, it went up under the 25-foot cap — and the design decisions that follow from five fewer feet are made years before anyone asks whether the building can become a residence.
What to settle before you price anything
- Which desk. Inside St. Anthony city limits the city issues the permit and a zoning permit comes first; outside, it is the county. The parcel decides, not the building type.
- Post and beam, or framed? This decides whether the stamped-plans rule applies. Ask the question in those words.
- Dwelling or accessory? This decides your height cap, and it is very hard to change later.
- Finished area versus shell area. Price them separately. A quote that blends them tells you nothing useful.
- Who has actually finished one here. Ask for an address you can drive past.
What a barndominium changes, and what it does not
| Changes | Stays exactly the same |
|---|---|
| Whether engineered stamped plans are mandatory, if the structure is free-standing post and beam | Which desk issues the permit — city or county, decided by the parcel |
| Which height cap applies, if the building is accessory rather than the dwelling | The 50 PSF design snow load for this district |
| How much of the floor area is finished versus shell, and therefore the price per square foot | Water and sewage: city hookups in town, well and septic outside |
| How quickly the shell goes up | The code list your build answers to |
Who to ask locally
Several St. Anthony firms build new single-family work and shop buildings, and a local builder who has done one of these is worth far more than a statewide post-frame brochure. The builders working out of this town are listed with their registration numbers on the main page of this site, and every one of those numbers is something you can check yourself.
If you want a shortcut, describe the building and the parcel on (208) 656-1745 and you will get pointed at the people here who have actually finished that work.
Related reading on this site
- St. Anthony issues its own building permits — which desk your barndominium file lands on
- The St. Anthony District snow load is 50 PSF — the design load your post-frame roof is engineered against
- What it costs to build a custom home in St. Anthony — why shell area and finished area have to be priced separately
- Reviews, references, and how to check a builder yourself — how to verify a post-frame builder has actually finished one here
Common questions
Can you build a barndominium in St. Anthony, Idaho?
Yes. Nothing in Fremont County's published building material prohibits a barndominium or a shop house, and post-frame residential construction is common on the valley floor. What governs it is the same permit path as any other dwelling, plus one county rule about stamped plans that catches most post-frame designs.
What is the one county rule that catches barndominium designs?
Fremont County's pre-construction checklist states, in emphasised capitals, that all free-standing post and beam structures require engineered stamped plans. There is no snow-load condition or size threshold attached to that sentence, so it applies regardless of how modest the building is.
Does that mean every barndominium needs an engineer?
It means every free-standing post and beam structure does, as the county has written the rule. Not every barndominium is post and beam — some are conventionally framed on a slab and only look like a barn. The construction method decides it, not the styling, so settle the method before you price the plans.
Is a barndominium cheaper than a conventional house here?
Sometimes, and less often than the marketing suggests. A post-frame shell can go up quickly for less than a stick-framed equivalent, but the finished living space inside it is priced like any other finished living space — insulation, mechanical, plumbing, cabinetry and windows do not care what holds the roof up.
How tall can it be?
Fremont County's checklist states buildings are not to exceed 30 feet, and accessory structures are not allowed to exceed 25. Whether your building is the dwelling or an accessory to one therefore changes the cap by five feet, which matters a great deal for a shop with living space over it.
Do the local builders do this work?
Several St. Anthony firms build new single-family construction and shops, but no local builder has publicly claimed the barndominium lane as a speciality — the companies marketing post-frame buildings into this valley are largely statewide operators based hundreds of miles away. Ask a local builder directly whether they have finished one, and ask to see it.
Does it change the permit path?
No. Inside St. Anthony city limits it is a city building permit preceded by a zoning permit; outside, it is a county building permit. The building type does not move you between desks — the parcel does.
Will a bank finance one?
That is a lender question and this site will not pretend otherwise. It is worth asking early, because the answer sometimes depends on how the finished structure is classified and on what comparable sales exist nearby — and both of those are settled long before you break ground.
Ask about a build in St. Anthony
Describe the parcel and roughly what you have in mind. What comes back is an honest read on which firms here take that kind of work, plus the one thing most people have not established yet: whether the city or the county will be reviewing your plans. Free, and nothing automated ever follows.
- Say where the ground is and what you intend to put on it.
- You are pointed toward the firms in this town with that work behind them.
- From there it is between you and them. No commission, no introduction fee, and nobody standing between you and your own contract.
One contact method is plenty — whichever you prefer. A human being writes back.