What Building Code Applies to Post Frame Construction?
Being a Plans Examiner in a Building Department would have to be one amongst this planet’s toughest jobs. Besides having to listen to clients who have their own ideas about how things should be built, there are volumes upon volumes of Building Code books and referenced texts.
A Hansen Pole Buildings’ client in Arizona recently had some extended discussions with a Plans Examiner in regards to appropriate Building Code for a residential detached accessory post frame building. Plans Examiner really wanted governing code to be 2012 IRC (International Residential Code). Of course all of this becomes confusing and confounding to this future building owner, as he had initially verified Code information with this same Building Department
previously and was advised 2018 IBC (International Building Code) would be applicable to his structure.
IRC has no language in it pertaining to post frame construction, while IBC indeed does. Your Building Department may require this building to be designed under IRC version 2012, even though later versions have greater accuracy for structural design due to advances in research and technology. This has to do with local jurisdiction code adoption policy.
Let’s look at how latest (2021) Codes handle what Code actually applies.
2021 IRC R101.2 Scope.
“The provisions of this code shall apply to the construction, alteration, movement, enlargement,replacement, repair, equipment, use and occupancy, location, removal and demolition of detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress and their accessory structures not more than three stories above grade plane in height.”
2021 IBC 101.2 Scope.
“The provisions of this code shall apply to the construction, alteration, relocation, enlargement, replacement, repair, equipment, use and occupancy, location, maintenance, removal and demolition of every building or structure or any appurtenances connected or attached to such buildings or structures.
Exception: Detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress, and their accessory structures not more than three stories above grade plane in height, shall comply with this code or the International Residential Code.”
2021 IRC R301.1.3 Engineered design.
Where a building of otherwise conventional construction contains structural elements exceeding the limits of Section R301 or otherwise not conforming to this code, these elements shall be designed in accordance with accepted engineering practice. The extent of such design need only demonstrate compliance of nonconventional elements with other applicable provisions and shall be compatible with the performance of the conventional framed system.
Engineered design in accordance with the International Building Code is permitted for buildings and structures, and parts thereof, included in the scope of this code.
Building a ‘barndominium’ or post-frame home or an accessory structure to a barndominium or post-frame home? Then IRC governs. Building an accessory structure when a home is not present on same parcel, then IBC governs.
IRC


Perhaps stick built construction’s biggest advantage is builders and tradespeople are very comfortable working in and around stick framing. All registered architects and most building inspectors are very familiar with stick framing. International Residential Code (IRC) provides a prescriptive ‘cook book’ to follow for adequate structural assembly, within certain limitations. These limitations include, but are not limited to, no story height of greater than 11 feet 7 inches (R301.3), no hurricane prone areas with a design wind speed of 130 mph or greater located south of Virginia, or 140 mph elsewhere (R301.2(5)B), and no ground snow loads over 70 psf (R301.2.3).
When I first began selling pole barn kits in Oregon, back in 1980, they were almost universally no permit required farm buildings. As our service area expanded into states such as California and Nevada, engineering was required in most instances, however there was never a concern about a pole building not being approved for use in any jurisdiction.
Lake Charles is in climate zone 2A. 2018’s International Energy Conservation Code prescriptively mandates (for your zone) a minimum R-38 value for ceilings and R-13 for wood framed walls. This would require 5-1/2″ in roof and 2″ in walls. You could go with 2″ of closed cell directly to underside of roof deck plus 6″ of open cell, or 2-1/4″ of closed cell with 5-1/2″ of Rockwool as alternatives.
While there does exist an actual ANSI (American National Standards Institute) definition of Eave Height – most builders and vendors are unawares or just plain choose not to use it. Somewhere your agreement should spell out what is proposed or provided so all have a clear understanding. (Please read more here:
Entry door width and heights, is door wood, steel, aluminum, vinyl covered, fiberglass? Jambs wood, steel, aluminum, vinyl covered wood? Doors and jambs finish painted or primed only? Crossbucks? Raised Panel? Glass? Wind rated? R value? Keyed lockset, dead bolts?
“Please be aware that the Land Development Code and adopted Building Codes 

The topic was brought up at the Aug. 6 meeting after Szokola reported he had seen more than one house come through requesting permits in which the house didn’t quite fit with what a typical house in the area might look like.
Ultimately, Planning Departments have every right to enforce aesthetic ordinances – as long as they are applied universally to all types of structural systems within a given occupancy classification (such as R-3 residential). What they cannot do is to regulate whether a Code conforming structural system may or may not be used. Should your jurisdiction try to prevent you from constructing a fully engineered post frame home – send me a copy of their written ordinance (not just anecdotal evidence) and I will go wage war for you.
In order to have your greatest possible resale value, you should have any lofted space designed so as to be considered as habitable space. International Residential Code (IRC)
Whoa there Nellie…..before getting all carried away, there are 14 essential questions to have on your Building Department Checklist, in order to ensure structural portions of your new building process goes off without a hitch. I will cover first seven today, finishing up tomorrow, so you have a chance to take notes, start your own home file folder of “what to do before I build”. Careful preparation will be key to having a successful post frame building outcome.

While post-frame construction is typically used in agricultural applications which are often (and in my humble opinion sadly) considered exempt from code compliance, more and more post-frame construction is either residential housing (IRC) or commercial (IBC) in nature. In these cases, changes which impact the code may have an effect on how post-frame buildings are constructed.