Davidson County 2018 IRC with Tennessee amendments

Barndominium Builders in Nashville, TN

Nashville and Davidson County are one government, which makes this the only place in Tennessee where the city and the county are not two separate building authorities with two sets of adopted codes. Metro Codes and Building Safety runs the building code out to the county line under Charter section 1.05, and it runs it on the 2024 International Residential Code, six editions ahead of the code most of the state is working from. The catch is where the land is: nearly all the acreage a building of this type wants sits in the general services district, outside the sewered urban core, on septic and under Metro's own health department.

Nashville at a glance

County: Davidson County
Population: 729,505
ZIP codes: 37013, 37072, 37076, 37080, 37115, 37138, 37189, 37201, 37203, 37204, 37205, 37206, 37207, 37208, 37209, 37210, 37211, 37212, 37214, 37215, 37216, 37217, 37218, 37219, 37220, 37221, 37228
Site visits: About 20 miles north of our Franklin office, straight up I-65

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Building conditions in Nashville

What actually changes from one Tennessee jurisdiction to the next: who issues the permit, whether the residential code is enforced there at all, what the structure has to be engineered to, and what the ground is like. These are the numbers your drawings have to satisfy.

Build conditions for Nashville, drawn from the sourced facts on this page. Every figure above is cited in the quick-facts panel below, with its source and vintage.

One building authority for the whole county

The Metropolitan Charter consolidates the City of Nashville with Davidson County and fixes the territory of the metropolitan government as the total area of the county. Section 1.05 lists the building code, plumbing code, electrical code and housing code among the functions performed throughout the entire general services district. So the building code reaches the county line from one department, which is true of nowhere else in Tennessee.

Metropolitan Charter of Nashville and Davidson County, sections 1.01, 1.02, 1.03 and 1.05, library.municode.com, code current through Ordinance BL2025-1141 approved 17 December 2025. Fetched 31 Aug 2026

Metro publishes a filled-in Table R301.2

Ground snow load 10 lbs. Wind design speed 115 mph. Topographic effects, special wind region and windborne debris zone all no. Weathering severe. Frost line depth 12 inches. Termite heavy. Winter design temperature 14 degrees F. Ice barrier underlayment not required. Tennessee leaves this table for each jurisdiction to complete, and most leave it blank; Metro substitutes a completed one in the adopting ordinance itself.

Metro Ordinance BL2025-898, section 16.08.014.F, amending Table R301.2 of the 2024 IRC. Passed on third reading 15 July 2025, approved by the Mayor 16 July 2025. nashville.legistar.com, fetched 31 Aug 2026

Seismic design category C, raised from B

Metro's 2020 code ordinance printed seismic design category B in Table R301.2. The 2025 ordinance prints C. That is a genuine change in the design input, and because Metro publishes the letter, no one has to read it off a map. A clear-span steel or post-frame building is engineered under R301.1.3 regardless, and the category is what the engineer feeds into the base connections and anchor bolts.

Metro Ordinance BL2025-898 section 16.08.014.F (category C) compared with Ordinance BL2020-458 section 16.08.014.F (category B), approved 9 November 2020. nashville.legistar.com, fetched 31 Aug 2026

Nashville is on the 2024 IRC

The Metropolitan Council adopted the 2024 International Residential Code, 2024 IBC, 2024 IECC, 2024 IEBC, IFGC, IMC, IPC and ISPSC, the 2023 National Electrical Code and 2017 ICC A117.1. Final passage 15 July 2025, signed the following day, effective immediately, with a 180-day grace period for projects already designed to the previous edition. Most of Tennessee is working from a residential code six editions older.

Metro Ordinance BL2025-898 section 16.08.010; Metro Codes and Building Safety, "Adopted Codes for Metro Nashville" and "Metro Adopts 2024 International Building Codes", nashville.gov, fetched 31 Aug 2026

Every footing needs reinforcement

Metro rewrites the general footing provision of the residential code: all exterior walls on continuous footings, footings on undisturbed natural soil or engineered fill, and "all concrete footing shall have minimum bottom reinforcement. Minimum reinforcement shall be 2-#4s continuous and shall be located a minimum of 3 inches clear from the bottom and side of the footing." The unamended code does not require steel in a plain concrete footing. Davidson County does, in every footing.

Metro Ordinance BL2025-898, section 16.08.014.N, amending the general footings section of the 2024 IRC. nashville.legistar.com, fetched 31 Aug 2026

Forty thousand square feet decides the shop

On a lot under 40,000 sq ft, a detached accessory building is capped at 700 sq ft or half the house's building coverage, whichever is greater, and never more than 2,500 sq ft, and it may not exceed one storey or sixteen feet. At 40,000 sq ft and above it may be two storeys or twenty-four feet. In AG and AR2a, where agricultural activities are permitted, the floor area cap does not apply at all. Sixteen feet is what kills a tall overhead door, not the floor area.

Metro Code of Ordinances sections 17.12.050 and 17.12.060.B, library.municode.com, code current through Ordinance BL2025-1141 approved 17 December 2025. Fetched 31 Aug 2026

Also worth knowing before you build in Nashville

Enforcement status, with a date on it: The State Fire Marshal's Office publishes every Tennessee jurisdiction as exempt, opt-out, or in the State Residential Building Program. Davidson County and Nashville appear on one line, marked exempt, alongside Belle Meade, Berry Hill, Forest Hills, Goodlettsville, Oak Hill and Ridgetop, all exempt. No part of Davidson County has opted out and no part is on state permits. The list is stamped accurate as of 21 August 2026.
Septic is a Metro Health matter, not a state one: Davidson is one of nine Tennessee counties that administers the subsurface sewage disposal programme under contract rather than through the state. Soil evaluation, percolation test monitoring, system design review and the permit all go through Metro Public Health at the Lentz Public Health Center, 2500 Charlotte Avenue, on (615) 340-5616. On a general services district site that call comes before the building permit conversation, not after.
Permit fees, and what a house does not pay: Residential building permits are $5.00 per $1,000 of total valuation. One- and two-family dwellings and townhouses are expressly excepted from the plans examination fee, which commercial work pays on top. Plumbing and gas or mechanical permits carry a $75.00 minimum each, a septic tank and disposal field line is $80.00, and a re-inspection is $50.00.
The energy tables run on 2009 numbers: Metro adopted the 2024 energy code and then amended the residential envelope back. The maximum assembly U-factor and minimum insulation R-value tables are deleted and replaced with the equivalents from the 2009 IRC, and air leakage testing is replaced with the 2009 Testing Option and Visual Inspection sections. An envelope specification taken from a national article about the current code will be stricter than what Davidson County actually enforces.
No sprinkler requirement for a detached house: Metro deletes the one- and two-family dwelling sprinkler section outright and writes a townhouse section that says a sprinkler system shall not be required. This is worth confirming locally rather than assuming, because Tennessee bars the state from mandating residential sprinklers but expressly allows a local government to go further. Nashville has gone the other way, in writing.
Nothing in the zoning code bans metal walls on a house: Title 17 contains one prohibition on sheet metal and corrugated metal, in section 17.24.210, and it applies to fencing used in landscape buffer yards inside the urban zoning overlay district. It does not reach the cladding of a dwelling. There is no material restriction on metal exterior walls for a site-built house in the county's zoning code, and no minimum floor area for a dwelling either.
Which service district a parcel sits in: The Charter created two districts: the general services district is the whole county, the urban services district was the old city and has grown by annexation where urban services followed. For 2025 the rates are $2.814 per $100 of assessed value in the urban district and $2.782 in the general district. The six satellite cities pay the general district rate plus their own. The acreage is almost all in the general district, which is also where septic and wells are.
Seven zoning authorities, one building authority: Consolidation in 1963 left six satellite cities holding their own charters, and Metro's own history notes they kept their police forces and zoning regulations. Belle Meade, Berry Hill, Forest Hills, Goodlettsville, Oak Hill and Ridgetop still set their own zoning. So the building code answer is county-wide while the zoning answer is not, and a parcel inside one of those six needs its zoning checked there.
The county is growing faster than any other in Tennessee: Davidson County reached 729,505 residents at 1 July 2024, adding 10,413 over the year. That was the largest numeric gain of any Tennessee county and Davidson's largest annual increase since 2015. Rutherford was second at 7,347. Growth of that shape is what keeps pressure on the remaining large parcels at the county edges.

Below the slab

The expensive surprises are in the ground, not the building

What moves a Tennessee budget is usually below grade: limestone sitting shallow, karst voids and sinkholes, and slope. Those are the same conditions that decide whether a septic field passes its soil and site evaluation, so the grading plan, the footing depth and the drainfield get resolved together rather than one at a time. We price the dirt before we price the building.

What we build in Nashville

All nine services are available across Davidson County. What a build costs depends far more on the parcel than on square footage, so we price against your land rather than publishing a rate card.

Barndominium Kits

Engineered barndominium shell packages delivered to your Tennessee lot, stamped for the criteria your county adopted.

Turnkey Builds

Start to finish barndominium construction: we handle permits, slab, shell, and full interior finish.

Custom Plans

Barndominium floor plans drawn to your land, your family, and the residential code your county actually enforces.

Post-Frame Homes

Pole barn construction adapted into full residences, with wide clear spans and fast dry-in.

Steel Construction

Red-iron and light-gauge steel framing: no rot, no termites, engineered to your county’s adopted wind criteria.

Shouses

Shop and house in one building: workspace and living space under a single roof and a single permit.

Metal Homes

Full metal-clad residences: low maintenance envelopes specified to your Tennessee climate zone.

Site Preparation

Clearing, grading, pad, drainage, and utilities: the work that decides whether the build goes smoothly.

Permitting & Engineering

Sealed structural engineering and the permit that depends on it, from submittal through final inspection.

What a build looks like

Three stages every Nashville project passes through, from a raw parcel to a finished home. Site work first, because that is where the budget is decided.

Stage one

The parcel

Zoning, setbacks, flood zone and utility access get checked before anything is drawn.

Stage two

Pad and permit

Clearing, grading and a compacted pad, while the submittal works through Davidson County.

Stage three

Frame to finish

Shell erected and dried in, then systems, insulation and interior finish through to CO.

Those are the rules for Davidson County. Tell us what you want to build and we will draw it to them.

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Where we build around Nashville

Davidson County and the rural land around it. The buildable acreage for a project this size usually sits outside the city limits, which is frequently what changes who issues your permit.

Our Nashville service area, covering Davidson County and the surrounding rural acreage. We build across this area from our office in Franklin, TN — this map marks the territory we serve, not a branch location.

Keep reading

The questions that usually come next once you know what Nashville allows.

Barndominium Cost Guide

Sourced per-square-foot ranges by tier and by size, with a calculator built on the same figures.

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Is It Legal in Tennessee?

Classification, zoning, the HOA gate, and why "nonresidential farm building" does not cover a home.

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How Long Does It Take?

Census build-duration data, and what actually sets the permit clock where you are building.

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Sources for this page

The primary documents behind the Nashville figures above. We would rather you checked them than took our word for it.

Nearby areas we build in

Others we cover in this part of Tennessee. The permitting authority, the adopted design criteria and the zoning can all differ from one to the next.

Building in Nashville: common questions

9 questions we get asked most often about building in Nashville. If yours is not on the list, ask it directly.

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Who issues the building permit for a barndominium in Nashville?

Metro Codes and Building Safety, at 800 President Ronald Reagan Way, on (615) 862-6500. Because Nashville and Davidson County are a single consolidated government, that one department covers the whole county rather than a city office and a county office covering different halves of it. The State Fire Marshal's Office lists Davidson County and Nashville together as an exempt jurisdiction, meaning local codes, a local permit and a local inspector. Registered contractors file through ePermits; everyone else starts at the Zoning Help Desk.

Which code edition applies, and does it match the rest of Tennessee?

It does not. Nashville is on the 2024 International Residential Code, adopted by ordinance BL2025-898 on 15 July 2025 and effective on the Mayor's signature the next day. Most of Tennessee is working from the 2018 edition. That matters for anything drawn to a stock plan set: a package specified against the state's edition will be reviewed here against a newer one, and the section numbers a national article quotes may resolve to a different subject.

What design criteria will an engineer be given for a Davidson County site?

Metro publishes them rather than leaving the table blank, which is unusual in Tennessee. Ground snow load 10 lbs, wind design speed 115 mph with no special wind region and no topographic effects, seismic design category C, weathering severe, frost line depth 12 inches, termite heavy, winter design temperature 14 degrees F, and no ice barrier underlayment required. A clear-span frame exceeds the prescriptive tables, so it is engineered under R301.1.3 and those figures are the inputs.

Can I put a big detached shop next to the house?

The lot size decides it. Under 40,000 square feet, a detached accessory building is limited to 700 square feet or half the house's building coverage, whichever is greater, capped at 2,500 square feet, and to one storey or sixteen feet in height. At 40,000 square feet and above it may be two storeys or twenty-four feet. In the AG and AR2a districts, where agricultural activities are permitted, the floor area cap does not apply. Sixteen feet is usually the constraint that bites first, because it rules out a tall overhead door with a truss above it.

Is there a minimum house size in Nashville's zoning?

No. Title 17 sets no minimum floor area for a dwelling in any district. Metro controls size through lot area, floor area ratio and impervious surface ratio instead. Nor does the zoning code restrict metal exterior walls on a site-built house: the only prohibition on sheet or corrugated metal is in section 17.24.210 and applies to fencing in landscape buffer yards within the urban zoning overlay district.

How much land do I need, and where in the county is it?

AR2a, the agricultural-residential district, has a two-acre minimum and permits single-family dwellings; AG requires five acres. Both sit in the general services district, the part of the county outside the old city's urban services boundary, where Metro sewer generally does not run. That is where the acreage is, and it means well and septic rather than a tap fee. Inside the urban services district the lot sizes get small quickly, down to 3,750 square feet.

Do I go to the state for the septic permit?

No. Davidson is one of nine Tennessee counties that runs the subsurface sewage disposal programme under contract, so the soil and site evaluation, the percolation test and the permit all go through Metro Public Health at the Lentz Public Health Center on (615) 340-5616. Get that conversation started before the building permit one, because on a general services district parcel the septic result can move the house.

What fees should I expect at permit issuance?

The residential building permit is $5.00 per $1,000 of total valuation, and one- and two-family dwellings are expressly excepted from the plans examination fee that commercial work pays. Plumbing and gas or mechanical permits carry a $75.00 minimum each. Separately, Metro Water Services charges a stormwater capacity fee of $0.71 per square foot of post-development impervious area, payable in full before grading permit approval, with projects under 800 square feet of impervious area exempt from stormwater infill review. A house, a shop and a drive together clear that threshold comfortably.

Does a contractor licence come into it?

Tennessee requires a state contractor licence for projects of $25,000 or more, counted on the complete project cost including labour and materials, and separate phases or contracts cannot be used to stay under the threshold. That number catches almost any barndominium. A property owner may build on their own property for personal use. Worth settling early, because it shapes who can hold the permit.

What clients say

4.9 out of 5 based on 8 reviews Placeholder content

Turnkey from a cleared lot to certificate of occupancy. What I appreciated most was that when plan review came back with comments, I heard about it the same day along with what they were doing about it.

Ray B. April 27, 2026

We had ten acres outside town and no idea what we could legally put on it. They pulled the zoning and the A-1 lot minimum before we spent anything on drawings, which saved us from buying plans for a building that would not have been approved.

Dale W. July 18, 2026

Ordered the shell kit and erected it with my brother-in-law over about six weekends. The drawings were clear, the bolt schedule matched what showed up on the truck, and the county inspector had no issues with the engineering.

Marisol T. June 2, 2026

Building in Nashville?

Start with the plan. Tell us what you want to build and we will draw it, then confirm what Davidson County will actually let you put on the parcel and what wind load it has to meet. That conversation costs nothing.

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