O’Neil Metal Buildings & Barndominiums is an Illinois builder. We’re based in Belleville in the Metro East, and we build turnkey post-frame barndominiums throughout all of Illinois: Southern Illinois, Central Illinois, Western Illinois, the Metro East, and north to Chicagoland. Looking for barndominium builders near me in Illinois? Wherever your land is in the state, we’re a local barndominium builder who will take the build from bare ground to a finished home.
Illinois buyers searching for a barndominium usually find two kinds of offers: kits you put up yourself, and shells that stop at the steel. O’Neil builds the whole house, and if you’d rather build it yourself, we’re also glad to sell you a material package.
Get a free turnkey quote or call (618) 337-6100.
Turnkey Means the Whole House, Not a Kit
A barndominium kit or an erected shell can look cheap on paper. Then you find out you’re the general contractor for everything inside: plumbing, HVAC, electrical, insulation, drywall, flooring, cabinets, and getting it all through inspection. An O’Neil turnkey barndominium covers all of it:
- Building permit. We handle the building permit on every build, with your county, township or municipality.
- Concrete. Site prep, footings and slab.
- The shell. Laminated-column post frame, engineered bolted trusses, 26-gauge steel roof and walls, doors and windows.
- Plumbing, HVAC and electrical. Roughed in and finished.
- Finished interiors. Walls, ceilings and finishes completed to your plan.
Septic and well approvals aren’t part of our scope. You arrange those through your county or local health department, and we can point you in the right direction.
One builder, one schedule, one point of contact. Read more about us as barndominium builders, or see our process step by step.
Barndominium kits in Illinois: kit, shell package or turnkey?
When you shop barndominium kits in Illinois, you’re usually looking at a DIY package from a kit seller. You still need a foundation, a crew to put it up, and someone to run the plumbing, HVAC, electrical and interior work, and that someone is usually you.
O’Neil gives Illinois buyers two other paths:
- Turnkey barndominium. We handle the building permit, concrete, the shell, plumbing, HVAC, electrical and finished interiors. You get the keys.
- Shell material package. For owners with their own crew. We supply the shell materials for your plan: posts/columns, trusses and framing, steel, trim, doors, windows and gutters. Concrete and labor aren’t included. See our steel and lumber supply.
Comparing a kit quote to a turnkey quote? Our barndominium cost guide shows how to compare shell to shell and turnkey to turnkey.
What to Know Before You Build a Barndominium in Illinois
Illinois is a long state, and building a barndominium in Chicagoland isn’t the same project as building one in Southern Illinois. Here’s what we plan around.
Zoning and permits: who has jurisdiction?
Depending on where your land sits, your approvals may come from a city or village, a township, the county, or a mix of them. Chicagoland and the larger metro areas tend to have more detailed building codes, design rules and inspection schedules. Many rural Illinois counties focus more on zoning, setbacks and minimum lot sizes. Subdivisions anywhere can have covenants on exterior materials or minimum home size, so check those before you buy.
Building a house on farm ground can bring its own questions too, like whether the parcel is zoned for a home and whether it meets the county’s acreage rules. Check those with the county before you commit to a plan. O’Neil handles the building permit on every build, and we can point you in the right direction on the rest.
Septic and wells go through your local health department
On rural Illinois land, the septic system and well are often the first approvals that matter. Those usually go through your county or local health department, and soil conditions can drive what kind of septic system your lot needs. You arrange these approvals yourself. O’Neil doesn’t handle septic or well permits, but we’re glad to point you in the right direction. Plan for both early. They also aren’t included in published per-square-foot barndominium averages (see cost below).
Prairie wind, flat ground and drainage
Much of Central and Northern Illinois is open, flat farmland. That’s great for building sites, but there’s often nothing to break the wind, and flat ground can drain slowly. We plan the building pad and grade so water moves away from the slab. The bolted truss-to-column connection described below is built for exactly this kind of exposure.
From the Shawnee Hills to the northern frost line
Southern Illinois has more rolling, wooded and hilly ground, so site prep and building placement take more planning there. Frost depth also changes as you move north, and local codes set footing requirements to match. We design the footings and slab for your location and your jurisdiction’s code, not a single plan for the whole state.
The O’Neil Post-Frame Difference
Columns that never touch dirt
This is the one to ask every Illinois post-frame builder about. Many pole barns and post-frame homes are built on posts buried in the ground, where the wood sits in soil and moisture. O’Neil columns never touch dirt. We use 3-ply and 4-ply laminated columns anchored to the concrete with heavy steel brackets, so the wood stays above grade.
Columns 8′ on center
Columns go in 8 feet on center for a stiffer frame under the walls, windows and finishes.
Girts and purlins 2′ on center, every purlin in a bracket
Wall girts and roof purlins are spaced 2 feet on center, and every purlin sits in its own bracket instead of being nailed on top of the truss. That gives the roof steel and ceilings a solid, even base.
Engineered trusses, always bolted
Every truss is engineered for the building and bolted to the columns, never just nailed. That’s a positive connection built for open-prairie wind and Illinois snow.
26-gauge steel with lifetime paint
Roof and wall panels are 26-gauge steel with a lifetime paint finish, for a low-maintenance exterior in the color you pick.
Illinois Barndominium Cost: Published Averages
Barndo Finder’s 2026 Barndominium Cost Report publishes a turnkey average of $140–$210 per square foot in Illinois. That’s a published third-party average, not an O’Neil price or quote. It excludes land, well, septic, driveway, site work and utility runs, and those can vary a lot on rural Illinois parcels.
Our barndominium cost guide explains what’s in those averages, how shell pricing differs from turnkey, and what to ask when you compare quotes. To get a number for your property, request a free quote. For the money side, start with our financing page.
Illinois Barndominium Builds We Design
Every O’Neil barndominium is custom. Illinois buyers often ask for:
- A home with an attached shop or oversized garage for equipment, vehicles or a business
- Wraparound or covered porches and lean-tos
- Open floor plans with vaulted great rooms
- Hobby spaces, like our golf simulator barndominiums
Browse barndominium plans and floor plan ideas.
Need a machine shed, horse barn or garage too? See our pole barns in Illinois. Land on the Missouri side? O’Neil builds throughout Illinois and Missouri, so we also cover barndominiums in Missouri.
Illinois Barndominium FAQs
Where in Illinois do you build barndominiums?
Everywhere in the state. O’Neil is based in Belleville in the Metro East, and we build throughout all of Illinois, from Southern Illinois and the Metro East through Central and Western Illinois to Chicagoland.
Do you sell barndominium kits in Illinois?
O’Neil builds turnkey barndominiums: the building permit, concrete, the shell, plumbing, HVAC, electrical and finished interiors, all handled by one builder. If you’d rather build it yourself, we’re also glad to sell material packages. See our steel and lumber supply page.
Can I build a barndominium on farmland in Illinois?
Often, yes, but it depends on the parcel’s zoning and your county’s rules for homes on agricultural land. Check the zoning with your county before you commit. O’Neil handles the building permit on every build. Septic and well approvals are arranged by the owner through the county or local health department, and we can point you in the right direction.
How much does a barndominium cost in Illinois?
Barndo Finder’s 2026 cost report publishes a turnkey average of $140–$210 per square foot in Illinois. That’s a published average, not an O’Neil price, and it excludes land, well, septic, driveway, site work and utility runs. Call (618) 337-6100 for a free quote on your land and plan.
How do your barndominiums hold up to Illinois wind?
Our trusses are engineered for each building and always bolted to the columns, never just nailed. Columns are 8 feet on center on steel brackets anchored to concrete, and every purlin sits in a bracket.
Do O’Neil’s posts go in the ground?
No. O’Neil columns never touch dirt. We use 3-ply and 4-ply laminated columns anchored to concrete with heavy steel brackets, so the wood stays out of the soil.
Start Your Illinois Barndominium
Tell us where your land is and how you want to live on it. O’Neil will put together a plan and a turnkey price, from the building permit through finished interiors.
Get a free turnkey quote or call (618) 337-6100.
Cost source: Barndo Finder, Barndominium Cost Report 2026 (Illinois turnkey average $140–$210/sq ft). A published average, not an O’Neil price or quote.