2-Story Barndominium in Kentucky

A two-storey version of this building reads differently from the road than the long single-level ones do. The gable end becomes two storeys of glass instead of one, there is usually a covered balcony over the entry porch, the ridge sits noticeably higher, and the whole thing occupies about half the ground a single-level house of the same living area would. Inside, the payoff is the same one every two-storey house gets: bedrooms away from the living space, a great room that can be open to the roof without giving up bedroom count, and a footprint small enough to fit a buildable pocket on a parcel that does not have forty flat acres in the middle of it. That last point is not a small thing here — a lot of Kentucky ground is sloping, wooded, karst or all three, and the cheapest square footage on a difficult site is the square footage stacked on top of what you already excavated for. The reason this page exists, though, is that the second storey is also the single decision that changes the engineering conversation most. The Department of Housing, Buildings and Construction wrote Kentucky its own prescriptive post-frame standard, Section R327 of the 2018 Kentucky Residential Code, Third Edition, and there is nothing like it in the model code the book is based on. Its second structural limitation is two words long: "Single story." DHBC wrote a complete recipe for a pole barn and never wrote one for a pole barn with an upstairs. That is not a prohibition — the section says in its own text what happens instead — but it means the design path for a two-storey building is decided before anyone picks a window.

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What actually changes with this feature

The look is the easy part. These are the decisions that follow from it.

Four limitations, not one, and they are not the same limitation

People who have read R327 tend to remember the 48-foot width cap, because it is the number that looks like a size limit. On a two-storey plan it is rarely the one that bites. Limitation 1, residential accessory structures, is left by any dwelling regardless of shape. Limitation 2, single story, is left by the floor. Limitation 6 caps wall height at 16 feet and limitation 7 caps mean roof height at 20 feet, and a genuine two-storey building normally clears both — nine feet of ceiling on each level plus the depth of the floor structure is most of 19 feet of wall before a rafter is drawn. Limitation 4, no attic storage, is a fifth departure for anyone planning to use the volume above the upper ceiling. Knowing which limits a design leaves is not academic paperwork: R327.1's escape paragraph sends the building to structural calculations, to Section R106.1, to Section R301 or to the Post Frame Building Design Manual, and the engineer's first question is which of the eight the drawing has left and by how much.

The published pier diameters were never asked to carry a floor

Table R327.3, Post Frame Pier Diameters, is the part of the section builders actually use, and it is indexed by one thing only: building width including the overhang, at 25, 28, 32, 36, 40, 44 and 48 feet, with one row of diameters for a 20 lb roof snow load and another for 30 lb. Footnote 2 states what those diameters were derived from — 2,000 psf assumed soil bearing capacity, and truss loads of 20 or 30 psf live or snow load on the top chord, 10 psf dead load on the top chord, 5 psf dead load on the bottom chord and no live load on the bottom chord. That is a roof, and nothing else. A second floor's dead load and its occupancy live load are not in that derivation anywhere, so the table's answer for a 40-foot-wide building describes a 40-foot-wide barn and not a 40-foot-wide two-storey house. The depth requirement in Section R327.3 is a separate matter and still worth knowing, because it surprises people: poured-in-place footings below all posts with the top of the footing not less than 48 inches below finished grade. That is an embedment rule rather than a frost rule, and it is a real excavation and concrete quantity at any number of storeys.

In the far west, a second storey can close the prescriptive path outright

DHBC's amended Section R301.2.2.2.5 states that prescriptive construction as regulated by the code shall not be used for irregular structures located in Seismic Design Categories D0, D1 and D2, and lists eight conditions that make a building irregular. Five of them are two-storey conditions. Condition 1: shear wall lines or braced wall panels not in one plane vertically from the foundation to the uppermost story in which they are required — a two-storey living end sitting beside a single-storey shop. Condition 4: an opening in a floor exceeding the lesser of 12 feet or 50 percent of the least floor dimension — a great room left open to the ridge. Condition 5: portions of a floor level vertically offset. Condition 6: shear walls and braced wall lines that do not occur in two perpendicular directions, which is the ordinary open-plan shape. Condition 8 sets a length-to-unbraced-dimension ratio of 1 for a one-story structure and 0.67 for other structures — a tighter test purely for having a second level. Table R301.2.2.1 puts Ballard, Carlisle, Fulton, Graves, Hickman and McCracken in D2, Calloway, Livingston and Marshall in D1, and Caldwell, Crittenden, Lyon, Trigg and Union in D0. On those parcels this is an engineered building by rule, not by preference.

The stair is Kentucky's own text, and it is more generous than the model

Section R311.4 requires egress from habitable levels by a ramp under Section R311.8 or a stairway under Section R311.7, and DHBC prints two of R311.7's dimensional rules in its own amended text rather than adopting them from the model. R311.7.5.1 sets a maximum riser height of 8 1/4 inches (210 mm). R311.7.5.2 sets a minimum tread depth of 9 inches (229 mm), with winder treads at 9 inches at the walk line and not less than 6 inches at any point in the clear width. Both are more permissive than the model code's 7 3/4-inch riser and 10-inch tread, and the practical consequence is real in a narrow clear-span plan: a steeper stair takes a shorter run, and the run is competing directly with the open floor of the room it lands in. It is worth drawing the stair in section at the same time as the plan, because the headroom, the landing and the guard at the upper edge are what actually decide where the second floor can start.

Section R327, structural limitation 2

The prescriptive post-frame recipe is two words long on this question: "Single story"

Section R327 of the 2018 Kentucky Residential Code, Third Edition, is a full prescriptive post-frame standard — pier diameters, column build-up, uplift blocks, knee bracing, purlins, diagonal roof bracing, a fastener schedule and figures — that DHBC wrote itself and that has no counterpart in the 2015 model on which the book is based. It opens by naming the eight structural limitations its requirements are good for: residential accessory structures; single story; metal roof on purlins with bracing and metal wall panels on girts; no attic storage; maximum building width of 48 feet including the overhang; maximum wall height of 16 feet; maximum mean roof height of 20 feet; and maximum post spacing of 8 feet. A two-storey dwelling leaves that list in four places at once, and it is worth being precise about which. Limitation 1 is left the moment the building is a house rather than a shop, at any number of storeys. Limitation 2 is left by the second floor itself. Limitations 6 and 7 are usually left by arithmetic — two 9-foot finished ceilings with a floor assembly between them is roughly 19 feet from slab to top plate before the roof begins, which is already past the 16-foot wall cap, and mean roof height is an average of the eave and the ridge rather than the eave alone, so it sits above the wall height by definition. R327.1's closing paragraph then says exactly what replaces the recipe: structural calculations as required by the residential building official, or design under the provisions of Section R106.1, or compliance with the structural design requirements of Section R301, or the alternative provisions — the Post Frame Building Design Manual — that Section R301.1.1 names. Read plainly, the code's own answer to "can I put a second floor on a post-frame building here" is yes, and it is engineered.

Common ways to build this

Common configurations we see. Yours does not have to match one exactly — this is a starting point for the conversation, not a catalog.

Two full levels on the same slab

Whole footprint stacked · smallest ground area per square foot of house

The most efficient version, and the one that suits difficult Kentucky ground best. A 30x40 footprint with a second floor over all of it is roughly 2,400 square feet of house sitting on 1,200 square feet of ground — half the excavation, half the slab, half the roof area and half the stormwater of the single-level building with the same living area. On a sloping wooded parcel, on a narrow ridge-top building envelope, or on ground where the geotechnical answer made every square foot of foundation expensive, that is the argument. What it costs you is stair, floor structure and height. The floor has to span the building, and a floor spanning 30 or 40 feet is a very different member from a roof truss spanning the same distance, because it carries occupancy live load rather than snow and it has to be stiff enough not to bounce. That is usually the moment a girder line and a row of columns reappear down the middle of a plan that was sold as clear span, and it is much cheaper to decide where they go than to discover them.

A two-storey house end against a single-storey shop

Two levels of living · one tall bay under the same ridge or a stepped one

This is the shape most people are actually describing when they say two-storey barndominium: the living end goes up two floors, the shop or equipment bay stays one tall storey, and the two are either under a continuous ridge or under a stepped roof with the shop as a lower wing. It photographs well and it uses the volume sensibly. Structurally it is also the textbook out-of-plane condition — the braced wall lines in the two-storey end do not continue down through the single-storey portion in one plane from the foundation to the uppermost story, which is the first of DHBC's eight irregularity conditions almost verbatim. In most of the state that is a design consideration. In the counties Table R301.2.2.1 assigns to D0, D1 or D2 it is the condition that removes the prescriptive path. There is a second consequence people miss: if the bay is used to park vehicles it is a private garage in the code's sense, and DHBC prints Section R302.5.1 in its own amendment text — openings from a private garage directly into a room used for sleeping purposes shall not be permitted, and other openings between the garage and the residence shall be solid wood or honeycomb-core steel doors not less than 1 3/8 inches thick, or 20-minute fire-rated doors.

Bedrooms upstairs over a great room open to the ridge

Double-height living space one side · upper level over the other

The interior everyone wants: a great room open the full height with the structure visible, an upper walkway along one side, and the bedrooms behind it. Worth knowing before you draw it is that the code treats the double-height space as a hole in the floor, and it puts a number on how big a hole is too big to build prescriptively. Irregularity condition 4 in Section R301.2.2.2.5 is an opening in a floor exceeding the lesser of 12 feet or 50 percent of the least floor dimension. In a 40-foot-wide building, half the least dimension is 20 feet, so the governing figure is the 12. A great room open to the ridge in one of these buildings is routinely 20 to 30 feet long. The exception to that condition requires the opening to be bounded by braced walls within four feet on all four sides, running the full height of the structure and bearing on continuous foundation walls or the basement slab — which is a demanding list, and its last requirement is one a post-frame pier grid does not meet, because a pier grid is neither a continuous foundation wall nor a basement slab. In the D0, D1 and D2 counties that combination is what sends the design to an engineer. Everywhere else it is still the reason the upper floor's edge, its guard and the bracing behind it deserve to be drawn early rather than detailed on site.

Living space above the shop or garage bay

Vehicles and work below · sleeping and living directly over

Putting the upper floor over the working bay rather than beside it is the most land-efficient version of all and the one with the most separation detail attached. Section R302.5.1, in DHBC's own amended text, bars an opening from a private garage directly into a room used for sleeping purposes, so the connection has to land in a hallway, a mudroom or a stair lobby rather than a bedroom. Section R302.6, the dwelling-to-garage separation table, is not among DHBC's amendments, so the model text stands and it treats habitable rooms above a garage as its own line: not less than 5/8-inch Type X gypsum board on the garage side of that ceiling, against 1/2-inch elsewhere. Two provisions that would otherwise apply here have been removed in Kentucky and it is more honest to say so than to imply protection that no longer exists. Section R302.13, fire protection of floors, is deleted in its entirety, so the membrane the model code asks for on the underside of engineered floor framing is not required. Sections R313.1 through R313.2.1, automatic fire sprinkler systems, are deleted in their entirety, so a one- or two-family dwelling is not required to be sprinklered. Neither deletion changes what an unprotected engineered floor does in a fire, and a floor with a workshop under it and bedrooms over it is the one place in this building type where that is worth spending money on regardless of what is required.

A steel rigid frame instead of posts

Second floor framed off the frame · clear span preserved at both levels

The other route to two storeys is to stop trying to make post-frame do it. A rigid-frame or cold-formed steel building carries the upper floor off the frame rather than off embedded wood columns, which keeps the clear span at both levels and puts the whole structure in the engineer's hands from the start rather than at the point R327 runs out. There is a neat asymmetry in the code worth noticing here. Section R301.1.1 lists six standards permitted as alternatives to Section R301, and one of them is the AISI Standard for Cold-Formed Steel Framing — Prescriptive Method for One- and Two-Family Dwellings. The state's own post-frame section is scoped to accessory structures and excludes dwellings by its first line; the cold-formed steel standard the same code names as an approved alternative is titled for dwellings. Section R301.1.1 adds that where engineered design is used in conjunction with these standards, the design shall comply with the Kentucky Building Code. The trade-offs are the ordinary ones — a steel frame is a different cost structure, a different erection sequence and a much more demanding thermal-break problem, since every frame member, girt and purlin is a continuous cold path — but on a two-storey building it removes an argument rather than starting one.

Ways to build this size

A footprint can go together several ways. These are the service lines most relevant to it.

Pole Barn Homes

Pole barn homes across Kentucky. KRC §R327 covers accessory barns, not houses — so a pole barn home is engineered by the code's own terms.

Steel Frame & Metal Building Homes

Metal building and steel-frame homes engineered to the 115 mph wind case and the Seismic Design Category your Kentucky county actually carries.

Custom Barndominium Plans

Barndominium plans drawn to Kentucky's published county design criteria — snow, wind, seismic, frost — with engineering where the code calls for it.

Turnkey Barndominium Builds

One contract for the whole build — site work, shell, finish — and for the separate Kentucky approvals: septic, floodplain, entrance, electrical.

2-Story Barndominium: common questions

8 questions we get asked most often about this footprint. If yours is not on the list, ask it directly.

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Can you build a two-storey barndominium in Kentucky?

Yes, and nothing in the residential code prohibits it. What changes is the design path rather than the permission. Section R327, the prescriptive post-frame standard DHBC wrote for this state, states its own scope in eight structural limitations, and the second of them is "Single story." The first is "Residential accessory structures," which any dwelling leaves regardless of height. So a two-storey post-frame home is outside that recipe on two counts before the wall-height and mean-roof-height caps are even measured. R327.1's closing paragraph then states what applies instead: structural calculations as required by the residential building official, or design under Section R106.1, or compliance with the structural design requirements of Section R301, or the alternative provisions in the Post Frame Building Design Manual that Section R301.1.1 names. Read as a whole, the code contemplates the building and routes it to engineering. The useful thing to take from this is that the engineering is a planned line item on a two-storey design, not a penalty imposed later, and the sooner the structural approach is settled the less the floor plan has to change around it.

Why does a second floor change the structure so much when the roof already spans the same distance?

Because a floor and a roof are not asked to do the same job. A roof truss spanning 40 feet carries snow and its own weight, it is allowed to deflect more than a floor is, and in a post-frame building it lands on columns at fixed spacing with nothing hung underneath it. A floor spanning the same 40 feet carries occupancy live load continuously, has to be stiff enough that it does not bounce underfoot, and delivers all of that load into the same columns the roof is already using. Table R327.3's own footnote makes the difference explicit: its published pier diameters were derived from 2,000 psf assumed soil bearing and truss loads of 20 or 30 psf live or snow on the top chord, 10 psf dead on the top chord, 5 psf dead on the bottom chord and no live load on the bottom chord. There is no floor in that load case. In practice this is the reason a two-storey plan so often ends up with a girder line and a row of columns down the middle, in a building type sold on the absence of exactly that. It is far better to place them deliberately — inside a wall, along a corridor, at a kitchen island run — than to have them arrive as a surprise at structural review.

Does a two-storey barndominium need an engineer?

In practical terms, plan on it. A dwelling of any height is already outside the prescriptive post-frame section's scope, and Section R327.1 routes anything outside its limitations to structural calculations, Section R106.1, Section R301 or the Post Frame Building Design Manual. In the far-western counties it is settled by rule rather than by judgement: Section R301.2.2.2.5 bars prescriptive construction for irregular structures in Seismic Design Categories D0, D1 and D2, and a second storey triggers several of the eight listed irregularity conditions — braced wall lines that are not in one plane from the foundation to the uppermost story, a floor opening over the stated size, vertically offset floor levels, and a tighter length-to-unbraced-dimension ratio that applies to other than one-storey structures. Table R301.2.2.1 assigns Ballard, Carlisle, Fulton, Graves, Hickman and McCracken to D2, Calloway, Livingston and Marshall to D1, and Caldwell, Crittenden, Lyon, Trigg and Union to D0. Note also what the code does not say: it does not state that a sealed design is required for every house in those counties. It says the prescriptive path is unavailable for irregular buildings and that irregular portions shall be designed in accordance with accepted engineering practice. That is a meaningful distinction, and it is why the honest answer is about the design path rather than about a stamp.

Is a two-storey barndominium cheaper to build than a single-storey one of the same size?

We publish no price of our own, and the direction of the answer is genuinely site-dependent rather than universal. What a second storey saves is the things measured in ground area: excavation, footings and piers, slab, roof structure, roofing area, gutters and the stormwater they discharge. What it adds is a floor structure that has to span the building, a stair and the floor area the stair consumes on both levels, taller walls and taller wall panels, more scaffolding and work at height, and a lateral system that has to carry load down through two levels rather than one. On flat, easy, cheap ground the single-storey version usually wins. On steep, wooded, rocky or geotechnically awkward ground — a great deal of Kentucky — the stacked version wins, sometimes decisively, because the expensive part was the ground and you bought half as much of it. On published figures generally, be careful: Kentucky-facing pages publish costs per square foot ranging from roughly $25 to about $300 without sourcing them, and the spread is mostly explained by scope, by site cost, and by whether the square footage in the denominator is finished living area or a blend of living area with an unconditioned shop. A two-storey building shifts that denominator by definition, since almost all of its added square footage is conditioned.

How steep can the stairs be, and how much room do they take?

DHBC prints the two governing dimensions in its own amended text rather than adopting the model's. Section R311.7.5.1 sets a maximum riser height of 8 1/4 inches (210 mm), measured vertically between the leading edges of adjacent treads, with the greatest riser in a flight not exceeding the smallest by more than 3/8 inch. Section R311.7.5.2 sets a minimum tread depth of 9 inches (229 mm), measured horizontally between the vertical planes of the foremost projection of adjacent treads, with the same 3/8-inch consistency rule. Winder treads must hold 9 inches at the walk line and not less than 6 inches at any point in the clear width. Both figures are more generous than the model code's 7 3/4-inch riser and 10-inch tread, which means a compliant stair here can be built in a shorter run than the same stair in a state that adopted the model unchanged. That matters in this building type more than in most, because the stair run is taken directly out of a long open plan and it competes with the room it lands in. Section R311.4 requires egress from habitable levels by a stairway under Section R311.7 or a ramp under Section R311.8, and the handrail, headroom and guard provisions all still apply — so draw the stair in section, not just in plan.

Do I need sprinklers, or fire protection under the second floor?

Not by state code, and it is worth being straight about that rather than implying otherwise. DHBC deletes Sections R313.1 through R313.2.1, automatic fire sprinkler systems, in their entirety, so the model code's sprinkler requirement for one- and two-family dwellings does not apply here. It also deletes Section R302.13, fire protection of floors, in its entirety, so the gypsum or structural-panel membrane the model asks for on the underside of engineered floor framing is not required either. Those are two of the clearest deletions in the whole amendment document and they both land on exactly this part of a two-storey house. What has not been deleted is the dwelling-to-garage separation. Section R302.5.1, printed in DHBC's own text, bars an opening from a private garage directly into a room used for sleeping purposes and sets the door construction for other openings, and Section R302.6, which is unamended, treats habitable rooms above a garage as its own case at 5/8-inch Type X gypsum board on the garage side. Beyond the code, this is a place where the building's own geometry argues for spending money: an unprotected engineered floor over a workshop, with bedrooms on top of it, is the assembly with the least margin in the building. Local requirements can also be stricter — under KRS 198B.060(1) permits, inspections and certificates of occupancy for a single-family residence are a local-government decision, so what is enforced changes at the county line and at the city limit inside it.

Where do the upstairs bedroom windows have to go?

Every sleeping room needs an escape opening, and on an upper level in a metal-clad wall that is a structural decision rather than a trim one. DHBC prints Section R310.1 in its own text: every sleeping room shall have at least one operable emergency escape and rescue opening, and where such openings are provided they shall have a sill height of not more than 44 inches measured from the finished floor to the bottom of the clear opening. The net clear opening dimensions have to be obtained by normal operation of the opening from the inside, and the openings must open directly into a public way, or to a yard or court that opens to a public way. DHBC also deletes the model's exception to R310.1 in its entirety, so there is no carve-out to argue about. In a post-frame or steel-clad wall, every one of those openings interrupts girts and wall panels on a wall that is also part of the bracing system, and on the upper level it is doing that in the same wall plane the lateral design is relying on. Locate the bedrooms and their escape openings at design stage, when the framer and the engineer can both see them, rather than after the panels are ordered to length.

Does a second storey change the foundation?

It changes what the foundation has to carry, and the published shortcut stops being usable. In post-frame, the whole building lands on discrete points, so the pier schedule is the foundation design. Section R327.3 requires poured-in-place concrete footings below all posts with the top of the footing not less than 48 inches below finished grade and diameters complying with Table R327.3, and footnote 1 sets pier footing thickness at not less than half the footing diameter. That depth requirement is an embedment rule for post-frame construction, and it applies whatever is above it. The diameters are the part that no longer applies: Table R327.3 is indexed by building width alone, and footnote 2 says its values assume 2,000 psf soil bearing and a roof-only load case with no live load on the bottom chord. A second floor is a load the table never carried. Then the ground gets its say. Table R401.4.1 lets presumptive load-bearing values be assumed in lieu of a complete geotechnical evaluation, but its footnote makes a soils investigation mandatory once the building official determines that soils with an allowable bearing capacity of less than 1,500 psf are likely to be present — and the table classifies materials, not conditions, so it has no line at all for a soil-filled solution feature. On karst ground — the Kentucky Geological Survey puts karst in 92 of Kentucky's 120 counties, across four named areas — doubling the load on a concentrated point is precisely the case where a geotechnical opinion is worth having before the design is fixed.

Keep reading

The pages that answer the next question this one raises.

Common barndominium sizes

What 30x40, 30x50 and 40x60 mean when the first number is the truss span, and how a second floor changes the arithmetic between footprint and living area.

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