Gently rolling Blackland Prairie grassland with deep dark cracking clay soil in the foreground and post oak along a fence line.
Denton County 2021 IRC as adopted here

Barndominium Builders in Lewisville, TX

Lewisville is wrapped around a US Army Corps of Engineers reservoir, and that single fact governs what can be built here and where. The city runs the 2021 International Residential Code with its own amendments, and it deleted the code's flood chapter outright — flood is handled instead by Lewisville's own Chapter 5.5, which requires a floodplain development permit and puts the lowest floor two feet above the base flood elevation. Above that sits a second, federal layer: land at or below about 535 feet around Lewisville Lake is owned outright by the government, and privately owned land below the 537.0-foot contour carries a flowage easement on which no structure for human habitation may be built at all. Land that photographs beautifully can be land you cannot put a house on. Lewisville is also built out — the city's largest ordinary residential lot is 18,000 square feet — so most people who want a barndominium on acreage end up buying north into Denton County or west toward Wise County and building there.

Lewisville at a glance

County
Denton County
Population
139,006
Where we build
Lewisville, Denton, Carrollton, Frisco

ZIPs 75056, 75057, 75067, 75077

Site visits
Site walks booked across Lewisville and the Denton County land around it
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Building conditions in Lewisville

What actually changes from one Texas 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 Lewisville , Denton County, Texas : design wind speed 115 mph. BUILD CONDITIONS LEWISVILLE, TXDenton County2021 IRCDESIGN WIND SPEED115 mphLewisville fills in IRC Table R301.2(1) at City Code § 4-32 and publishes 115 mph 3-second gust,equivalent to 76 mph fastest mile. The Manual J design-criteria table is deleted.ZONING · AO AGRICULTURE - OPEN SPACE; R-18 IS…1 acre (43,560 sq ft) in AO; 18,000…The Unified Development Code describes AO as a holdingclassification applied on annexation, and expects AO land to be…IMPACT AND PERMIT FEESCapital recovery feesLewisville charges capital recovery fees alongside building permitfees. Both schedules sit outside the code of ordinances — City Code…WHO ISSUES THE PERMITCity of Lewisville Building Services…151 W. Church Street, Lewisville, TX 75057. 972.219.3470. Permitapplications, contractor registration and inspection requests all…
Build conditions for Lewisville, drawn from the sourced facts on this page. Every figure above is cited in the quick-facts panel below, with its source and vintage.
Adopted residential code
Lewisville runs the 2021 International Residential Code, adopted with Appendix AT and Appendix AW by Ordinance 0612-23-ORD on 6 November 2023, together with the 2021 International Energy Conservation Code.

City of Lewisville Code of Ordinances §§ 4-31 and 4-29 (Municode Library)

The flowage easement at 537 feet
The Corps of Engineers holds a flowage easement over privately owned land below the 537.0-foot contour around Lewisville Lake — the right to flood it in perpetuity. On that land the Corps prohibits constructing or maintaining any structure for human habitation, while a building not intended for habitation may be permitted by the District Engineer. So the living half of a barndominium has to sit above the contour.

U.S. Army Corps of Engineers, Fort Worth District — Lewisville Lake, Adjacent Landowner Information

Finished floor in a flood hazard area
New residential construction in a special flood hazard area must have its lowest floor — including all machinery and equipment serving the building — elevated two feet above the base flood elevation, certified to the floodplain administrator by a registered professional engineer, architect or land surveyor.

City of Lewisville Code of Ordinances § 5.5-17(1), Flood Damage Prevention

Every foundation gets an engineer
Lewisville amends IRC R401.2 to add: every foundation and footing, or any size addition to an existing foundation, shall be designed and sealed by a Texas-registered engineer. On Blackland Prairie clay that is a requirement the state's engineering law reaches anyway, but here the city states it directly.

City of Lewisville Code of Ordinances § 4-32, amendment to IRC Section R401.2

Published design criteria
Lewisville fills in IRC Table R301.2(1) itself: 115 mph three-second gust wind speed, seismic design category A, frost line depth 6 inches, winter design temperature 22 degrees F, moderate weathering, ground snow load 5 lb/ft, air freezing index 150 and a mean annual temperature of 64.9 degrees F.

City of Lewisville Code of Ordinances § 4-32, Table R301.2(1) as filled in

Minimum lot area
Lewisville's Agriculture - Open Space district requires one acre and caps buildings at 10 percent lot coverage with 100-foot yards on all sides, and the code treats it as a holding zone applied on annexation. The largest ordinary single-family district, R-18, has a minimum lot of 18,000 square feet — under half an acre.

Lewisville Unified Development Code §§ VI.5.1 and VI.5.2 (Municode Library)

Also worth knowing before you build in Lewisville

Climate zone, from the city's own words
Lewisville's energy amendments state that the city is in a warm humid location in Climate Zone 3A of the IECC. Denton County is 3A on both the pre-2021 and 2021 climate maps, so unlike the Dallas County suburbs the zone here does not shift with the edition.

City of Lewisville Code of Ordinances § 4-30, Energy conservation code — Amendments

Termite exposure is 'very heavy'
The termite row of Lewisville's Table R301.2(1) reads 'Very Heavy' — the same value Dallas and Fort Worth publish. That rating is what closes off foam plastic below grade at the foundation, and it shapes how the slab edge and any sill detail get built.

City of Lewisville Code of Ordinances § 4-32, Table R301.2(1) as filled in

The IRC flood chapter is deleted
Lewisville deletes IRC Section R322, Flood-Resistant Construction, in its entirety, and its Table R301.2(1) enters 'Local Code' in the flood hazards cell. Flood is governed by the city's own Chapter 5.5 instead. The city also deletes IRC Section R313 on automatic sprinkler systems.

City of Lewisville Code of Ordinances § 4-32, amendments to IRC Sections R322 and R313

Which flood maps apply
Lewisville adopts two Flood Insurance Studies by reference: Denton County and Incorporated Areas dated 18 April 2011, and Dallas County and Incorporated Areas dated 7 July 2014, each with its Flood Insurance Rate Map of the same date, plus any revisions.

City of Lewisville Code of Ordinances § 5.5-6, Basis for establishing the areas of special flood hazard

Corps-owned land around the lake
Land around Lewisville Lake at or below roughly 535 feet is owned in fee by the U.S. Government, taking in the lake at its 522-foot pool and a substantial band above it. The boundary is marked with brass-capped concrete monuments and often fenced. Constructing buildings, roads or other facilities on that public land is prohibited.

U.S. Army Corps of Engineers, Fort Worth District — Lewisville Lake, Fee Land

The floodway is a harder line than the floodplain
Within the mapped regulatory floodway, encroachments are prohibited outright — fill, new construction, substantial improvements and other development — unless hydrologic and hydraulic analyses demonstrate no increase in flood levels. Being in the floodplain and being in the floodway are two very different answers.

City of Lewisville Code of Ordinances § 5.5-20, Floodways

Contractor registration
Anyone providing services that involve erecting, constructing, enlarging, altering, moving or improving a structure must register with the city before working in Lewisville. Registration runs one year from issue, and where it is required no permit will be issued and inspections may be held while it has lapsed.

City of Lewisville Code of Ordinances §§ 4-551 and 4-555, Contractor Registration

An excavator grading a compacted building pad on a cleared lot, with survey stakes and a drainage swale visible.
Below the slab

The expensive surprises are in the ground, not the building

What moves a Texas budget is usually below grade, and it is soil rather than rock: shrink-swell clay. The Blackland Prairie and the Gulf Coast clays move enough between a wet season and a dry one to drive the foundation design across the state's largest markets, which is why several DFW cities require an engineer's seal on the foundation of every new house. Those are the same conditions that decide whether a septic field passes its soil and site evaluation, so the grading plan, 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 Lewisville

All nine of our services — kits, custom plans, post-frame and steel construction, site preparation, permitting and engineering, through to turnkey builds — are available across Denton County. What a project costs depends far more on the parcel than on square footage, so we work from your land rather than from a rate card.

See what we build

What a build looks like

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

Aerial view of an undeveloped rural lot with cleared grass, a live oak and cedar elm treeline, and a pale gravel access track.
Stage one

The parcel

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

An excavator grading a compacted building pad on a cleared lot, with survey stakes and a drainage swale visible.
Stage two

Pad and permit

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

A finished barndominium at dusk with warm interior lighting glowing through its large windows.
Stage three

Frame to finish

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

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

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Where we build around Lewisville

Denton 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 Lewisville service area, covering Denton County and the surrounding rural acreage. This map marks the territory we serve, not a branch location.

Keep reading

The questions that usually come next once you know what Lewisville 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 Texas?

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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Nearby areas we build in

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

Denton

Denton County
Carrollton

Dallas County
Frisco

Collin County

Building in Lewisville: common questions

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

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Can I put a barndominium on land next to Lake Lewisville?
It depends entirely on elevation, and there are two separate federal lines before the city's rules even start. Land at or below about 535 feet around the lake is owned outright by the U.S. Government, and buildings on it are prohibited. Privately owned land below the 537.0-foot contour carries a Corps flowage easement — the government's right to flood it in perpetuity — and on flowage easement land the Corps prohibits constructing or maintaining any structure for human habitation, including mobile homes and travel trailers. A shop or barn that is not intended for habitation may be permitted there in writing by the District Engineer, but the living space cannot be. The Corps' own advice to buyers is to establish on the ground whether there is enough room above the upper extent of the flowage easement to place a house and its septic system before you buy.
What is a floodplain development permit, and do I need one?
If your parcel is in a special flood hazard area, yes. Lewisville City Code § 5.5-7 says plainly that a floodplain development permit is required. This is not a local quirk: Texas Water Code § 16.3145 directs the governing body of each city and county to adopt whatever ordinances or orders are needed to stay eligible for the National Flood Insurance Program, so every Texas city and county has floodplain rules of some kind. That matters well beyond Lewisville — in an unincorporated Texas county with no residential building code at all, the floodplain development permit can be one of the very few permits that does exist. The application has to show the elevation of the lowest floor of the proposed structure relative to mean sea level, along with the site plan and any proposed cut or fill.
How high does the finished floor have to be?
In a special flood hazard area where a base flood elevation has been established, Lewisville requires the lowest floor — including any basement and all machinery and equipment serving the building — to be two feet above the base flood elevation. That is a foot more than the National Flood Insurance Program minimum. A registered professional engineer, architect or land surveyor has to certify to the floodplain administrator that the standard is met, which in practice means a surveyed elevation on the record before and after construction. If the parcel is in the mapped floodway rather than merely the floodplain, the answer changes: encroachments there are prohibited unless engineering analysis shows they would not raise flood levels.
Which building code does Lewisville enforce, and has it changed anything?
Lewisville adopts the 2021 International Residential Code with Appendices AT and AW, by Ordinance 0612-23-ORD adopted 6 November 2023, plus the 2021 International Energy Conservation Code. Texas cities may amend a code they adopt — including by deleting parts of it — and Lewisville has. It fills in Table R301.2(1) with its own design values, deletes IRC Section R322 on flood-resistant construction so that the city's own flood chapter governs instead, deletes Section R313 on automatic sprinkler systems, deletes the IRC's energy chapter in favour of the separately adopted IECC, and adds a paragraph to R401.2 requiring every foundation and footing to be designed and sealed by a Texas-registered engineer.
Is there any acreage left inside Lewisville?
Very little, and the zoning tells the story. Lewisville is hemmed in by the lake on one side and I-35E through the middle, and its largest ordinary single-family district, R-18, has a minimum lot of 18,000 square feet — under half an acre. The one-acre Agriculture - Open Space district exists mainly as a holding classification applied when land is annexed; the code itself says AO property is expected to be rezoned as the city develops, and it caps buildings at 10 percent lot coverage with 100-foot yards. If you want a barndominium on real acreage in this part of the metroplex, the honest answer is to look north into unincorporated Denton County beyond the built-up ring, or west toward Wise County, where parcels are larger and the county has no general residential building code in its unincorporated area.
Who do I talk to, and what does the city need from a contractor?
Building Services handles plan review, permitting and inspections for the city, at 151 W. Church Street, Lewisville, TX 75057, on 972.219.3470; applications, contractor registration and inspection requests all go through the city's MGO Connect portal. Anyone performing work that involves erecting, constructing, enlarging, altering, moving or improving a structure has to register with the city first — registration lasts a year, and while it is lapsed no permit will be issued and inspections can be held. Note that Texas has no state licence for a residential building contractor, so city registration is a local requirement, not a state one. The floodplain administrator, for anything touching Chapter 5.5, is the city manager or a designee.
Why does the foundation need an engineer here?
Two reasons that arrive at the same place. Lewisville's own amendment to IRC R401.2 requires every foundation and footing — and any size addition to an existing foundation — to be designed and sealed by a Texas-registered engineer, with no exception for a house. Separately, this part of North Texas sits on shrink-swell clay, and Texas engineering law removes the ordinary private-dwelling exemption for a slab on expansive soil, while the IRC hands expansive-soil foundations to the building code's own engineered-design provisions. A barndominium's long clear spans and concentrated column loads make the slab design the part of the build worth spending on.

Building in Lewisville?

Start with the plan. Tell us what you want to build and we will draw it, then confirm what Denton 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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