Wake, Chatham & Durham Counties 2018 NC Residential Code, statewide

Barndominium Builders in Cary, NC

Cary is a town — legally a town, at 183,582 people, larger than every North Carolina city except Charlotte, Raleigh, Greensboro, Durham, Winston-Salem and Fayetteville — and it spans three counties: Wake, Chatham and Durham. Its 61.09 square miles of land carry all of those people, and that is the honest problem with a Cary barndominium. This is not a place where acreage comes to market. Wake County is 11.7 percent farmland and Durham County is 8.8 percent; Chatham, immediately west, is 26.1 percent, and Johnston, to the south-east, is 34.4 percent. So a Cary buyer almost always ends up building in Chatham or Johnston and commuting back, and this page exists to say that plainly rather than to imply otherwise. What is genuinely useful about Cary itself is the jurisdiction question. Under G.S. 160D-202 a municipality's zoning, subdivision regulation and building-code enforcement reach one to three miles past the corporate line depending on population — while its property tax and its ballot do not. A parcel outside Cary that looks entirely rural, taxed by the county and voting in county elections, can still be under the town's development rules. And because Cary straddles three counties, which one your parcel falls in decides the environmental health department that permits your septic system and your well, and the fee schedule and fee basis your permit is priced on.

Cary at a glance

Counties: Wake, Chatham & Durham Counties
City rules outside city limits: Under G.S. 160D-202 a parcel outside the town line can still be under Cary's zoning, subdivision and building-code enforcement — while Cary property tax and Cary elections stop at the corporate line.
Population: 183,582
ZIP codes: 27511, 27513, 27518, 27519, 27523
Site visits: Same week across the Triangle

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Building conditions in Cary

The building code does not change at a county line here. Under § 143-138(e) the North Carolina State Building Code applies throughout the state, and a city or county may adopt only a fire prevention code and floodplain regulations of its own — there is no general local amendment power, so there are no county amendments to look up. The edition in force is still the 2018 NC Residential Code, effective 1 January 2019; the 2024 edition has been delayed three times and carries no effective date at all. What genuinely differs is who issues the permit and inspects the work, what that office charges, how the parcel is zoned, what the local floodplain ordinance requires of the foundation — and two design numbers the code publishes county by county, the ultimate design wind speed and the seismic design category. The rest of Table R301.2 is set once for everyone: a flat 20 psf roof live load, a 12-inch frost line, Moderate weathering, and termite protection required everywhere in the state with no exemption. There is no ground snow load column in the residential code at all.

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

A town of 183,582, in three counties

Cary is incorporated as a town, not a city, and the Census Bureau's 2025 subcounty estimates put it at 183,582 — up from a 2020 base of 174,787. The same file splits it across three counties: 179,502 in Wake, 4,079 in Chatham and one person in Durham. That one-person county part is not a rounding artefact; it is a corporate boundary that clips a Durham County parcel. Fifty-eight North Carolina municipalities span a county line; four of them span three, and Cary is one — with Durham city, Hickory and Sharpsburg. High Point spans four.

U.S. Census Bureau, Vintage 2025 subcounty population estimates, sub-est2025_37.csv, census.gov

61 square miles, and all of it spoken for

The 2025 Census Gazetteer gives Cary 61.091 square miles of land and 1.114 of water. Put 183,582 people on that and it works out to roughly three thousand to the square mile. Chatham County, whose line Cary crosses on its west side, covers 681 square miles at 125 people per square mile. That contrast is the entire reason a Cary barndominium is usually a Chatham or Johnston barndominium with a Cary commute.

U.S. Census Bureau, 2025 Gazetteer place file for North Carolina, and Vintage 2025 county estimates, census.gov

Where the land actually is

The 2022 Census of Agriculture measures Wake County at 664 farms on 62,323 acres — 11.7 percent of the county, median farm 32 acres — and Durham County at 212 farms on 16,166 acres, 8.8 percent, median 27. Chatham runs 1,076 farms on 114,051 acres, 26.1 percent, median 49; Johnston runs 964 farms on 174,111 acres, 34.4 percent, median 40. Chatham grew 11.6 percent since 2020 and Johnston 18.7 percent, the largest absolute gain of any ring county in the state. Those two counties are where a Cary buyer's search should start.

USDA NASS, 2022 Census of Agriculture, county tables for Wake, Durham, Chatham and Johnston, nass.usda.gov; U.S. Census Bureau Vintage 2025 county estimates, census.gov

Town rules, county taxes, county ballot

G.S. 160D-202 lets a North Carolina municipality enforce its zoning, its subdivision regulation, its building code and its minimum housing standards outside its own limits — one mile under 10,000 people, two miles from 10,000 to 24,999, three miles at 25,000 or more. Cary is far into the top tier. What does not travel with those powers is the town's law enforcement, its trash collection, its noise and nuisance ordinances, its business licensing, its property tax and its elections. A parcel in the ETJ is regulated by a council its owner cannot vote for.

UNC School of Government, Extraterritorial Jurisdiction in Planning and Development Regulation, sog.unc.edu; Coates' Canons, Extraterritorial Jurisdiction in a Nutshell, canons.sog.unc.edu

Wake County ETJ is frozen until the end of 2028

House Bill 173, "Temporarily Limit ETJ Expansion in Wake County", bars any municipality from expanding the territory over which it exercises extraterritorial jurisdiction in Wake County beyond what it exercised on 1 January 2025. It applies to Wake County only and expires 31 December 2028. Wake County's own planning department states that, in compliance with it, the county will not proceed with municipal requests for ETJ extension. So the Wake-side ETJ map a buyer checks today is the map that stands for the next two years — which is a rare piece of certainty in a rule that has been repealed town by town elsewhere in the state.

Wake County Planning and Development Services, Extraterritorial Jurisdiction (ETJ), wake.gov/departments-government/planning-development-inspections/planning/extraterritorial-jurisdiction-etj (read 6 Sep 2026)

The county line changes what the permit costs and how it is measured

Wake County's published residential permit fee is $75 plus $0.25 per square foot of gross floor area, and the schedule defines that area as gross floor area finished within the inside perimeter of the exterior walls, with no deduction for garage, corridors, stairs, closets or other features — so an unheated shop bay is fully billable. That one fee covers all trades. Chatham County's is $0.40 per square foot with a $400 minimum, plus a $3,500 education impact fee, and its published schedule does not define whether that square footage is heated or under-roof. Chatham also prices its septic improvement permit by bedroom count, $150 for two bedrooms rising to $400 for six. Same house, same design, different county line, different bill and a different rule for measuring it.

Wake County Permits and Inspections Fee Schedule, wake.gov/departments-government/permits-and-inspections/permits-inspections-fee-schedule; Chatham County Central Permitting Fee Schedule and Public Health Environmental Health fee schedule, chathamcountync.gov (both read 5 Sep 2026)

Also worth knowing before you build in Cary

Septic follows the county, and it gates the building permit: On the Wake side, Wake County Environmental Services publishes an Improvement Permit at $400, a Construction Authorization at $400 that includes the Operation Permit, and a new private drinking-water well permit at $800 covering the inspections, sample collection and laboratory analysis. 15A NCAC 18E .0201(e) requires all documentation for a wastewater system to be kept by the local health department in the county where the permit is issued and the property taxes are paid — so a Cary-addressed parcel on the Chatham side is a Chatham County septic file. And .0201(c) sets the order: on issuance of the Construction Authorization the applicant may obtain a building permit. The septic result comes first, and under .0509(a) it is binary — suitable or unsuitable, with "provisionally suitable" abolished when 18E replaced the old .1900 rules on 1 January 2024.
Two nutrient strategies meet near here: The Neuse riparian buffer rule, 15A NCAC 02B .0714, expressly covers the Falls of the Neuse Reservoir watershed; the Jordan strategy covers the Jordan Lake watershed including portions of the Haw River basin. Which one reaches a parcel depends on which way it drains, and NC DEQ publishes the basin boundaries. Both buffers are 50 feet in two zones — 30 feet undisturbed and 20 more — and at Jordan the legislature suspended the new-development stormwater rule (02B .0265) but did not suspend the buffer rule (02B .0267). A blue line on the USGS or NRCS soil survey map is what creates the buffer; an on-site determination, good for five years, can remove it.
Four offices, and the mailing address names none of them: Inside the town limits the Town of Cary's Inspections and Permits staff reviews and issues building, electrical, mechanical and plumbing permits. Step outside them and the answer changes with the county: Wake County Planning and Development Services, Chatham County, or Durham County. A mailing address that reads Cary tells you nothing about which of those four offices holds your file, and neither does the postal city on a listing.

Below the slab

The expensive surprises are in the ground, not the building

What moves a North Carolina budget is usually below grade, and the thing most often got wrong is which clay to worry about. Cecil — the red Piedmont clay everyone pictures, and the state soil — is kaolinitic and low shrink-swell; it does not heave. The soil that does is Iredell, formed over diabase and gabbro, which the USDA describes as vertic, very high shrink-swell, with a perched water table a foot or two down from December through April. The tell is colour: Cecil is red and Iredell is dark grey-brown, and they sit within a few miles of each other across the central Piedmont. West of that the question stops being clay and becomes slope, rock and colluvium; east of the fall line it becomes water, and in the Tidewater it becomes organic soil that subsides irreversibly once it is drained. Then the same ground decides the septic system, and North Carolina rewrote those rules recently enough that most of what is published about them is out of date. 15A NCAC 18E replaced the old subchapter on 1 January 2024 and was amended again on 1 June 2026: the site is classified on soil morphology — the word "percolation" does not appear anywhere in it — and there is no "provisionally suitable" any more, only suitable or unsuitable, on a single failed parameter. There is no statewide minimum lot size either; the area you need is derived from the soil result and then doubled, because a site that cannot fit both the initial field and its repair area is unsuitable. And the order matters more than people expect: the county health department's Improvement Permit and Construction Authorization come first, and the building permit is available on the strength of the Construction Authorization, not before it. One more thing that catches people: disturb more than an acre and you need an approved erosion and sedimentation control plan in hand before work starts, with penalties up to $5,000 a day, and a pad plus a drive plus a drainfield plus a laydown area crosses an acre faster than it sounds. So the site work, the foundation 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 Cary

All nine services are available in Cary. 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 shell packages drawn to your own county's wind and seismic numbers under the 2018 NC Residential Code, with the exclusions written down.

Custom Plans

Barndominium floor plans drawn for your parcel, your county's design figures and the septic system your bedroom count will actually need.

Metal Homes

Metal building homes finished to live in — envelope, insulation, condensation control and interior finish specified to your NC county's climate zone.

See all nine services

What a build looks like

Three stages every Cary 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 septic authorization and the building submittal work through whichever offices cover your parcel.

Stage three

Frame to finish

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

Those are the rules where you are building in Cary. Tell us what you want to build and we will draw it to them.

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Where we build around Cary

Wake, Chatham & Durham Counties and the rural land around it. The buildable acreage for a project this size usually sits outside the town limits — which does not automatically put it under the county, because a town's zoning and building-code enforcement reach one to three miles past its limits into its extraterritorial jurisdiction. Inside the limits, in the ETJ, or in neither are three different answers to who issues your permit.

The Cary service area, including the rural acreage outside the built-up edge, which is where the parcels big enough for a build like this usually sit. The map marks the territory we build in. It is not a branch location, and there is no office at this pin.

Keep reading

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

Barndominium Cost Guide

What the named, dated sources actually publish for North Carolina, with a calculator built on the same figures.

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Is It Legal in North Carolina?

Why a "farm building" is defined as nonresidential, and the ten-acre right § 160D-903(b) gives you in exchange for building to the code.

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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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Nearby areas we build in

Others we cover nearby. Every North Carolina municipality sits inside a county — there are no independent cities here — but that does not settle who regulates a given parcel. A town's zoning, subdivision rules and building-code enforcement extend one to three miles beyond its limits, by population, into what the statute calls its extraterritorial jurisdiction; town taxes and town elections do not follow. So the office that issues the permit, what it charges and how the land is zoned can all differ from one card to the next, and the mailing address will not tell you which case you are in.

Chatham County

Wake County

Apex

Wake & Chatham Counties

Johnston County

Building in Cary: common questions

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

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Can I actually build a barndominium in Cary?

Very rarely, and it is fairer to say so than to imply otherwise. Cary is a town of 183,582 people on 61 square miles, and Wake County as a whole is only 11.7 percent farmland with a median farm of 32 acres. Land inside the town limits at a size and price that suits this building type essentially does not come to market. The realistic answer for a Cary buyer is Chatham County to the west or Johnston County to the south-east — 26.1 percent and 34.4 percent farmland respectively, and two of the fastest-growing counties in the Triangle ring. Both are inside a normal commute, and both are places where a 5 to 20 acre parcel is an ordinary thing to buy.

Cary is a city, isn't it?

No. Cary is incorporated as a town and has stayed one at 183,582 people, which is larger than every North Carolina city except six. The distinction has no effect on the building code — N.C.G.S. § 143-138(e) makes the State Building Code apply throughout the state and there is no general local building-code amendment power anywhere in North Carolina — but it does affect how a parcel is described in records, and it is the sort of detail that tells you whether a page was written by someone who looked.

Which county am I actually in?

It is worth checking, because Cary crosses three lines. The 2025 Census estimates split the town's population 179,502 in Wake, 4,079 in Chatham and one in Durham. The county matters more than the town does for a build: it decides which health department issues your septic improvement permit and construction authorization, which fee schedule prices your building permit, and how that fee is measured. Wake charges $75 plus $0.25 per square foot with no deduction for a garage; Chatham charges $0.40 per square foot with a $400 minimum plus a $3,500 education impact fee. The county's parcel viewer or register of deeds settles the question for a specific address.

My land is outside the town limits. Whose rules apply?

Ask three questions in order. Is the parcel inside the town line? Then town zoning and town inspections. Is it inside the town's extraterritorial jurisdiction? Then the town's zoning, subdivision regulation and building-code enforcement apply under G.S. 160D-202 — up to three miles out for a municipality of 25,000 or more — while the town's property tax and the town's elections stop at the corporate line. Is it in neither? Then the county alone. The ETJ boundary is recorded with the county register of deeds and shown on the town's official zoning map. In Wake County the map is unusually stable right now: House Bill 173 froze ETJ expansion at its 1 January 2025 extent until 31 December 2028.

What are the design numbers for a Triangle build?

Wake, Chatham and Durham are all unlisted in Table R301.2(4) of the 2018 NC Residential Code, so each carries the default 115 mph ultimate design wind speed — the code's floor. None is on the Table R301.2(7) list of Seismic Design Category C counties, so all three are A or B, and all three are IECC climate zone 4A. Statewide and true here as everywhere: a flat 20 psf roof live load, a 12-inch frost line depth, Moderate weathering, and termite protection required in all of North Carolina at a Moderate-Heavy severity. There is no ground snow load column in the code — Section R301.2.3 is deleted — and R403.3, the frost-protected shallow foundation route, is deleted too, which matters for a slab-on-grade design.

Is there a building-code difference between the three counties?

No, and that is worth stating because the opposite is the natural assumption. N.C.G.S. § 143-138(e) provides that the State Building Code applies throughout the state, and the only things a local government may adopt of its own are a fire prevention code and floodplain regulations. There is no general local building-code amendment power in North Carolina, so there is no set of county code amendments to go and compare. What genuinely differs between Wake, Chatham and Durham is zoning, the fee schedule, the health department and floodplain regulation — and those differences are real and worth checking.

Do I need an engineer?

For a metal or post-frame building, usually yes. Section R301.1.2 requires framing systems outside the code's prescriptive scope to demonstrate equivalent detailing, and North Carolina gives no residential exemption from the engineering requirement — § 83A-13(c)(1) exempts a family residence from the architect requirement, but § 89C-25 has no equivalent carve-out for engineering. A barndominium in the Triangle is normally an engineered building sealed by a professional engineer licensed in North Carolina, and that is a real cost to plan for rather than a surprise.

Building in Cary?

Start with the plan. Tell us what you want to build and we will draw it, then confirm which office issues the permit for your parcel, what it will let you put there, and what wind load it has to meet. That conversation costs nothing.

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