The Williamson County Deck Permit Guide: Five Jurisdictions, Five Different Permit Paths

"Williamson County permit" does not mean what most homeowners think it means. The county is home to five different permitting authorities, each with its own building codes department, its own adopted code edition, its own submittal portal, its own fee schedule, and its own review timeline. Pulling a deck permit at the wrong jurisdiction is the single most common project-delay cause we see on new client projects, and it is entirely avoidable if the homeowner or contractor knows which jurisdiction the property actually sits in before the application is filed.

This guide is the verified reference, current as of 2026, with every address, phone number, code edition, and process detail confirmed direct from each jurisdiction's official .gov source.

Why "Williamson County Permit" Doesn't Mean What You Think

The confusion starts with the address. A home in Franklin has a Franklin TN mailing address. A home in Brentwood has a Brentwood TN mailing address. A home in Nolensville has a Nolensville TN mailing address. The mailing address tells you what the U.S. Postal Service considers your community to be — but it does not necessarily tell you what jurisdiction issues your building permits.

Williamson County contains five distinct residential building permit jurisdictions:

1. City of Franklin — incorporated city with its own Building & Neighborhood Services department.
2. City of Brentwood — incorporated city with its own Codes Department.
3. Town of Nolensville — incorporated town with its own Codes Department.
4. Town of Thompson's Station — incorporated town with its own Building & Codes Department.
5. Williamson County (unincorporated) — county-administered Building Codes Division for properties outside any incorporated city or town.

If your property is inside the city limits of Franklin, Brentwood, Nolensville, or Thompson's Station, you pull permits from that municipality regardless of what your mailing address says. If your property is outside any incorporated municipality, you pull permits from Williamson County's Building Codes Division.

Two additional Williamson County towns — Fairview and Spring Hill — also operate their own codes departments. Spring Hill straddles the Williamson-Maury county line and includes properties in both counties; the city department handles permits for the Williamson County side. We do not work projects in Fairview or the Maury County side of Spring Hill regularly enough to cover those jurisdictions in detail here.

Decision Tree: Which Jurisdiction Is Your Property In?

The fastest way to confirm your jurisdiction is to look up your property on the Williamson County Property Assessor's website. The property record will show whether the parcel is inside the corporate limits of an incorporated municipality. If it is, that municipality's codes department issues your permits. If it shows the parcel as outside any incorporated boundary, Williamson County issues your permits.

The general geographic pattern:

• Franklin — central Williamson County, including most of the master-planned subdivisions (Westhaven, McKay's Mill, Berry Farms, Fieldstone Farms) and downtown Franklin.
• Brentwood — northern Williamson County along the Davidson County border, including Governors Club, Annandale, Hampton Reserve, Concord Park, and surrounding neighborhoods.
• Nolensville — eastern Williamson County, including Bent Creek, Burkitt Place, Brittain Downs, McFarlin Woods, and other production-builder subdivisions.
• Thompson's Station — southern Williamson County including Tollgate Village, Bridgemore, and other communities along Columbia Pike.
• Williamson County (unincorporated) — outside all incorporated areas, including Legends Ridge, Laurelbrooke, and the rural-residential parcels along the county's outer geography.

This is a general pattern only. The specific corporate limits zigzag in places, and properties on the boundary of two jurisdictions can be in one or the other. The Property Assessor lookup is the authoritative answer.

City of Franklin — 2024 IRC

Department: Building & Neighborhood Services Address: 109 3rd Avenue South, Franklin, TN 37064 (Franklin City Hall) Code Edition: 2024 International Residential Code, effective January 1, 2026

The City of Franklin operates the most current code edition of any jurisdiction in our service area, having moved to the 2024 IRC effective the start of 2026. The 2024 edition tightened lateral load connection requirements, clarified ledger attachment specifications for cantilevered conditions, and added explicit guidance on guard infill at openings near grade-level changes. Decks designed to the 2018 IRC will receive review comments for the missing 2024 provisions.

The Franklin permit process includes an additional consideration that other jurisdictions do not have: the Downtown Franklin National Register Historic District operates under a Historic Zoning Commission overlay that reviews exterior alterations on properties within the boundary. If your address is inside the historic district (roughly 5th Avenue North to 1st Avenue South, a few blocks east and west of Main Street), HZC approval is required before the building permit is issued. The HZC meets monthly, and the total review-plus-permit timeline runs forty-five to sixty days for downtown projects.

For Franklin properties outside the historic district, the standard permit timeline runs five to seven business days on a complete submittal.

City of Brentwood — 2018 IRC

Department: Codes Department Address: 5211 Maryland Way, Brentwood, TN 37027 (Brentwood City Hall, Maryland Farms corporate corridor) Code Edition: 2018 International Residential Code

The City of Brentwood operates under the 2018 IRC for residential construction. The 2018 edition is the same code in effect at the City of Belle Meade and Metro Nashville/Davidson County, but a different edition than Franklin or Nolensville (both 2024) or unincorporated Williamson County (2021).

Brentwood's R-1 zoning establishes a one-acre minimum lot size with twenty-five-foot side-yard setbacks and forty-foot rear-yard setbacks. The setback math affects deck footprint placement on every Brentwood project. Lots in the OSRD (Open Space Residential Development) zoning that governs many master-planned subdivisions allow lot clustering inside the development boundary while maintaining overall density.

Brentwood's permit timeline runs five to seven business days on a complete submittal. The Codes Department uses the City of Brentwood's online portal for submittals.

Town of Nolensville — 2024 I-Codes

Department: Codes Department Codes Enforcement Director: Monty Kapavik (615-776-6692) Plans Examiner: Chris Bridgewater (615-776-6698) Senior Permit Specialist: Janna Pastin (615-776-6694) Permit Specialist: Hope King (615-776-6686) Code Edition: 2024 International Code Council (I-Codes) suite, including 2024 IRC for residential Permit Portal: GeoCivix Construction Hours within town limits: Monday-Saturday 7am-7pm (or dark, whichever first); Sunday 9am-7pm

The Town of Nolensville adopted the 2024 I-Codes during fiscal year 2024-2025, putting the town on the most current code edition in our service area alongside the City of Franklin. The 2024 IRC R507 includes the most current lateral load connection requirements, ledger attachment specifications, and guard infill provisions.

Reinspection fees apply for failed inspections starting November 1, 2025. Permit submittals go through the GeoCivix portal. Most production-builder subdivisions inside Nolensville (Bent Creek, Burkitt Place, Brittain Downs, McFarlin Woods, Sherwood Green Estates, Catalina, Concord Park, Burberry Glen) operate independent ARCs that review parallel to the town building permit.

Town of Thompson's Station — 2021 IRC

Department: Building and Codes (Community Development) Address: 1110 Fountain View Blvd, Thompson's Station, TN 37179 Mailing: PO Box 100, Thompson's Station, TN 37179 Phone: 615-794-4333 / Fax: 615-794-3313 Code Edition: 2021 International Residential Code Permit Portal: GeoCivix (same portal as Nolensville)

Thompson's Station is exempt from the State of Tennessee fire marshal residential inspection program because the town operates its own building department and inspections. The 2021 IRC is the in-force edition; this is one edition behind Nolensville and Franklin (both 2024) and one edition ahead of Brentwood, Belle Meade, and Metro Nashville (all 2018).

For deck projects in Thompson's Station subdivisions including Tollgate Village, Bridgemore, and the surrounding communities along Columbia Pike, the town's GeoCivix portal handles submittals. Inspection requests run through the same portal.

Williamson County (Unincorporated) — 2021 IRC

Department: Williamson County Building Codes Division Address: 1320 West Main Street, Suite 400, Franklin, TN 37064 Phone: (615) 790-5718 / Fax: (615) 595-1224 Hours: 8:00 am – 4:30 pm Code Edition: 2021 International Residential Code, effective August 1, 2025 Plan Review: Electronic Plan Review Submittal & Review system available

Williamson County's Building Codes Division administers permits for properties outside any incorporated city or town. The 2021 IRC took effect August 1, 2025; deck projects designed before that date were under the prior code edition. New submittals are reviewed against 2021 IRC.

The State Electrical Permit Wrinkle: As of June 8, 2023, electrical permits for projects in unincorporated Williamson County are NOT issued by the County Building Codes Division. Electrical permits go through the State of Tennessee at core.tn.gov. This is a separate submittal from the building permit, runs on a separate timeline, and requires a state-licensed electrical contractor to pull. For deck projects with electrical work (lighting, ceiling fans, outlets), this means coordinating two permit processes rather than one. Most contractors who only work inside incorporated cities are not used to this requirement and miss it on their first unincorporated-county project.

Properties served by the unincorporated Williamson County permit office include Legends Ridge (off Hillsboro Road), Laurelbrooke (off Sneed Road), and rural-residential properties throughout the county's outer geography.

The Standard Submittal Package

Despite the five different jurisdictions, the residential deck permit submittal package is broadly similar across all of them. The core documents required:

The completed application for the specific jurisdiction. Each city or town has its own form. Williamson County uses its own form for unincorporated properties.

Two stamped copies of the framing plan showing footing locations and depths, post sizes and locations, beam sizes and connections, joist sizes and spacing, ledger attachment details with lateral load connection per IRC R507, and railing system specifications.

The property survey or plot plan with the proposed deck footprint drawn at scale and the dimensions to property lines (setback distances) called out. Most jurisdictions accept a property survey from the original home purchase or a current scaled drawing if the survey is unavailable.

Manufacturer specifications for any composite or PVC decking, the railing system, and any specialty hardware. The manufacturer documentation supports both the warranty and the code review.

The subdivision ARC approval letter for properties inside an architectural review committee jurisdiction. Most premium subdivisions in Williamson County operate ARCs that review separately from the town or city permit. Franklin's master-planned subdivisions, Brentwood's gated communities, Nolensville's production-builder communities, and Thompson's Station's neighborhood developments all operate ARCs.

The Historic Zoning Commission approval letter for properties inside the Downtown Franklin National Register Historic District, the Belmont-Hillsboro Conservation Overlay (Davidson side), or other historic preservation overlays. Historic district approval is required before the building permit is issued.

A submittal that includes all of these documents in a single complete package will move through review faster than a submittal that requires the reviewer to ask for missing items.

Subdivision ARC Reviews That Run Parallel

The architectural review committee at your subdivision is not the same as the city or town building permit. Both reviews are required before construction begins. The ARC review focuses on architectural compatibility — does the new deck design match the neighborhood's design standards. The building permit review focuses on structural compliance with the IRC.

The standard practice is to file both packages the same week so the timelines run together rather than sequentially. ARC review timelines vary by subdivision — typically two to six weeks depending on the committee's meeting schedule and packet completeness.

Common Permit Mistakes That Slow Projects

The most common reasons a Williamson County deck permit gets delayed:

Wrong jurisdiction. The homeowner files at Williamson County Building Codes when the property is inside a city limit, or files at the City of Franklin when the property is in unincorporated county. The county or city flags the application, the homeowner has to refile correctly, and the project loses a week or two.

Missing lateral load connection on the framing plan. R507 requires positive mechanical lateral load connection on every attached deck. Older framing plans that copy from pre-2018 designs frequently miss this. The reviewer kicks the plan back for revision.

Setback dimensions not shown. The plot plan needs the deck footprint with measured distances to property lines. Plans showing the deck footprint without setback dimensions get rejected.

Missing manufacturer specifications. Composite decking, PVC decking, and railing system manufacturer specifications are part of a complete submittal. Plans that reference "composite decking" without a specific manufacturer and product line miss the documentation requirement.

No ARC approval for subdivision properties. Building permits issued without subdivision ARC approval can lead to stop-work orders if the ARC discovers the project mid-construction.

Wrong code edition specifications. Plans designed to the 2018 IRC submitted to a 2024 IRC jurisdiction (Franklin, Nolensville) will receive review comments for the missing 2024 provisions. Conversely, plans designed to 2024 specifications submitted in 2018-edition jurisdictions are typically accepted because newer-spec exceeds the minimum.

Electrical permit not pulled separately for unincorporated county projects. As noted, electrical work in unincorporated Williamson County goes through the State at core.tn.gov. Projects that include electrical work but only pull the building permit will fail final inspection until the electrical permit is also obtained.

Timeline From Contract to Final Inspection

The realistic timeline from signed contract to final inspection on a Williamson County deck project depends on jurisdiction, scope, and seasonal demand. A representative timeline:

• Design and ARC packet preparation: one to two weeks
• ARC review: two to six weeks (subdivision-dependent)
• Building permit submittal and review: one to two weeks (jurisdiction-dependent)
• Materials ordering and delivery: one to four weeks (composite/PVC lead times have stabilized in 2026 but can vary)
• Construction: one to four weeks (project-scope dependent)
• Final inspection scheduling: one week
• Total typical timeline: eight to fourteen weeks from contract to final inspection

Premium projects with custom architectural elements, historic district reviews, or substantial structural rebuilds run longer. Simple resurface projects on existing framing run shorter.

When to Hire a Contractor Who Pulls Permits vs. DIY

Tennessee state law allows a homeowner to pull permits and act as their own contractor on residential projects on their own property. The legal allowance does not equal practical advisability for most homeowners.

For projects we recommend the homeowner pull permits and self-perform: simple repair work on existing structures with no structural alterations, replacing existing decking boards on existing framing without changing the structure, and similar maintenance-grade work where the homeowner has the carpentry skills and the time available.

For projects we recommend hiring a licensed contractor who pulls permits and assumes the liability: any new construction, any structural alteration, any project that requires ARC review, any project in a historic district, any project with electrical or plumbing work, and any project where the homeowner does not have time to be physically present for the multiple inspections required.

The cost premium of hiring a licensed contractor over self-performing is real but it includes the permit-process management, the ARC interface, the inspection scheduling, the trade coordination, the warranty, and the Tennessee general contractor liability insurance that protects the property owner from construction-defect claims. For deck projects on premium properties the contractor cost is typically meaningful relative to the home value but small relative to the consequences of permit problems or structural issues.

Deck Craft is a Tennessee-licensed general contractor (TN GC #78722) and a member of the Williamson County Chamber of Commerce. We pull permits for every project we contract, file ARC packets in parallel, schedule inspections at the right intervals, and carry the contractor liability insurance that protects the homeowner from defect claims for the life of the warranty.

Quick Reference: Jurisdictions at a Glance

This guide is a working reference produced by a Tennessee-licensed general contractor based on direct verification of each jurisdiction's published codes department information current as of 2026. Code editions are updated periodically; permit fees and review timelines are subject to change. Verify current information at submittal time directly with the relevant jurisdiction.

Deck Craft TN GC #78722 Williamson County Chamber of Commerce member Building decks in Williamson County since 1999 615.555.0123 (please replace with current line) 231 Public Square, Franklin, TN 37064 deckcraftnashville.com