Nine to fifteen months from a land contract to keys is our planning assumption for a turnkey barndominium in the St. Louis ring; a shell goes up in one to two weeks once the slab or post holes are ready, which is why "six to eight weeks" gets quoted and why it misleads. The months are in the ground and the county, not the building.
The calendar
| Phase | Weeks | What happens | What stretches it |
|---|---|---|---|
| Land and feasibility | 2–6 | County/city check, covenant pull, floodplain, soil evaluation with profile pit, septic design, power-line distance and extension estimate, 911 address request | A failed soil evaluation; a parcel inside a city; waiting on the co-op's extension estimate |
| Design and engineering | 3–6 | Plan, SDC C post-frame engineering, specification and allowance schedule, fixed-price estimate | Plan changes; custom spans |
| Financing | 4–8 (overlaps) | Construction-to-permanent application, appraisal, closing | The appraisal comps search; USDA processing |
| County approvals | 1–8 | See by county below | Franklin plan review; Warren's septic-before-structure sequence |
| Site work | 2–6 | Clearing, grading, driveway base, entrance, well drilling, septic installation (after permit), electric service scheduling | Wet spring ground; driller schedule; utility scheduling |
| Slab or post holes | 1–2 | Under-slab plumbing (inspected in code counties), vapor retarder, pour, cure | Weather; perched water in Nov–Apr on fragipan soils |
| Shell | 1–3 | Posts, trusses, steel, doors, windows | Material lead time (4–8 weeks, ordered during site work) |
| Finish-out | 12–24 | Interior framing, MEP rough-ins and inspections, insulation, drywall, finishes, fixtures | Trade scheduling; allowance decisions; inspection cycles |
| Final | 1–3 | Final inspections and certificate of occupancy (code counties); fire-district sign-off (Warren, Lincoln); lender's final draw; walkthrough | A failed final; a missing septic final |
By county
- Franklin: plan review on the 2021 IRC adds two to six weeks up front; each county inspection takes a day or two to schedule; the permit is good for 365 days. The county sewage permit runs through the Building Department.
- Jefferson: plan review and inspections on the published 2015 code; confirm the current edition at application.
- Warren: fastest county approvals, in a fixed order — 911 address, septic permit (soil scientist's evaluation, pits), then the $150 structure permit. No county inspections, so the schedule is the lender's draw inspector's. The septic permit expires in a year.
- Lincoln: no county permit at all; the Health Department septic permit and, in a mapped area, the floodplain permit are the only county steps; the fire district's electrical/occupancy check is the last. Shortest paperwork in the ring.
- St. Charles: county plan review and inspections on the 2021 county code; zoning check for the five-acre and 800-square-foot minimums.
Season
Spring is the ring's wet season; the perched water tables on Winfield and Union soils are highest November through April. The sequence that works with the ground: close on land and do feasibility in winter or spring, site work and slab in late summer or fall, shell before the holidays, finish-out through winter, move in by late spring. A spring start pushes the slab into the wet season and the shell into the busiest post-frame months.
Frequently asked questions
Can it be done in six months? A shell on Lincoln County land with power at the road and a conventional septic — yes. A turnkey home in Franklin County — no.
What is the single biggest delay? The soil evaluation that nobody ordered before closing. Second: the electric line extension nobody priced.
Does winter stop construction? Slabs and septic installation are weather-dependent; the shell and the interior are not. Winter finish-outs are what we recommend.
How long is the shell lead time? Four to eight weeks for materials, ordered during site work so it arrives when the slab cures.
Next step
Custom barndominiums run this calendar as one contract. Related: land, septic and well · permits and codes by county · the complete guide.