🪵 Deck / Porch permit in Montana
An attached or freestanding outdoor platform, usually wood or composite, elevated above grade or at grade level. Here is the Montana-specific rule: who issues it, typical fees, timeline, go / no-go, and the official source to verify.
Deck / Porch permit in Montana
The Montana rule for a deck / porch, with fee range, timeline, go / no-go, and the official source.
Montana
🪵 Deck / Porch
Exact permit fees are set by the local building department. WikEst shows the published or code-based range where one exists, linked to its official source — verify the final amount at the source before budgeting.
🪵 Deck / Porch permit fee in Montana
ConditionalGenerally allowedcity authority
Permit fee range
Where enforced, fees follow the local schedule; verify locally.
Typical timeline
Where enforced, simple decks often over-the-counter to a few weeks.
Setback
—
Exempt if
Freestanding decks not over 30 in above grade are typically exempt (2021 IRC R105.2). Billings requires a permit for decks over 30 in above grade.
Exempt criteria: Freestanding deck not attached and not over 30 in above grade is generally exempt (2021 IRC R105.2).
In certified cities a permit is required for elevated or attached decks. In non-certified areas, single-family homes are exempt from the state building permit. State trade permits still apply.
Official sources: MT Dept. of Labor & Industry — Building Codes Program · City of Billings, MT — Building Division FAQ (adopted codes & permits)
Representative cities for Montana: Billings, Missoula.
All 20 project fee ranges in Montana
Official-source ranges where published; “By local jurisdiction” means no flat fee is published and the amount is set case by case.
| Project | Permit? | Authority | Fee range | Go / no-go |
|---|---|---|---|---|
| 🏠 Accessory Dwelling Unit (ADU) | conditional | city | Where a certified city/county enforces, fees follow that jurisdiction; in non-certified areas a single-family home is exempt from the state building permit (trade permits still apply). Verify locally. | case-by-case |
| 🪵 Deck / Porch | conditional | city | Where enforced, fees follow the local schedule; verify locally. | allowed |
| 🧱 Fence / Wall | conditional | city | Where enforced, fencing permits apply above local height limits; verify locally. | allowed |
| 🛖 Shed / Outbuilding | conditional | city | Where enforced, small detached sheds may be exempt; verify locally. | allowed |
| 🪜 Basement Finish | conditional | city | Where a certified city enforces, a building permit fee applies; in non-certified areas the state building permit is exempt for single-family homes (trade permits still apply). Verify locally. | allowed |
| 🚗 Garage / Carport | conditional | city | Where enforced, attached garages (additions) are permitted; verify locally. | allowed |
| ☀️ Rooftop Solar PV | yes | state | Electrical permit required statewide by the MT DLI Building Codes Program (NEC); local jurisdictions may also be involved. | allowed |
| 🌡️ HVAC Replacement | yes | state | Mechanical permit required statewide by the MT DLI Building Codes Program; licensed contractors perform the work. | allowed |
| 🍳 Kitchen Remodel | conditional | city | Where enforced, a building permit plus trade permits apply; verify locally. | allowed |
| 🛁 Bathroom Remodel | conditional | city | Where enforced, a building permit plus trade permits apply; verify locally. | allowed |
| 🏗️ Room Addition | conditional | city | Where a certified city enforces, a building permit based on valuation applies; in non-certified areas the state building permit is exempt for single-family homes (trade permits still apply). Verify locally. | allowed |
| 🪟 Window / Door Replacement | conditional | city | Where enforced, a permit fee applies if enlarging the opening; in-kind swap often exempt. Verify locally. | allowed |
| 🏘️ Roof Replacement | conditional | city | Where enforced, an in-kind re-roof may be exempt; structural deck replacement requires a permit. Verify locally. | allowed |
| 🅿️ Driveway / Parking Pad | conditional | city | No building permit for private flatwork where enforced; a right-of-way permit may be needed. Verify locally. | allowed |
| 🏊 Swimming Pool / Spa | conditional | city | Where enforced, a building permit plus barrier fencing applies; verify locally. | allowed |
| 🧱 Retaining Wall | conditional | city | Where enforced, a permit applies if over 4 ft; verify locally. | allowed |
| 💥 Demolition / Teardown | yes | city | Demolition permit fee set by the issuing authority; verify locally. | allowed |
| 🚰 Septic System | yes | county | Septic permit fee set by the local environmental/health authority; engineered systems cost more. | allowed |
| 🔌 EV Charger | conditional | city | Electrical permit; fee set by the issuing authority. | allowed |
| ⚡ Standby Generator | conditional | city | Mechanical/electrical permit; fee set by the issuing authority. | allowed |
Montana rule at a glance
Needs permit
conditional
Issuing authority
city
Typical fee
Where enforced, fees follow the local schedule; verify locally.
Typical timeline
Where enforced, simple decks often over-the-counter to a few weeks.
Setback
—
Exempt if
Freestanding decks not over 30 in above grade are typically exempt (2021 IRC R105.2). Billings requires a permit for decks over 30 in above grade.
In certified cities a permit is required for elevated or attached decks. In non-certified areas, single-family homes are exempt from the state building permit. State trade permits still apply.
Official sources for this rule: MT Dept. of Labor & Industry — Building Codes Program · City of Billings, MT — Building Division FAQ (adopted codes & permits)
Frequently asked questions
Does a deck / porch need a permit in Montana?
In Montana, a deck / porch is conditional / size-dependent. Issuance is at the city level. Confirm the exact threshold with the local building department using the sources on this page.
Who issues the deck / porch permit in Montana?
Montana permits for this project are handled at the city level — usually the city or county building department. Use the county permit authority lookup to find the exact office for your property.
How much does a deck / porch permit cost in Montana?
Fees are set locally in Montana and are not a single statewide number. Open the official authority link on this page for the current schedule.
What exemptions apply to a deck / porch in Montana?
A common threshold: Freestanding decks not over 30 in above grade are typically exempt (2021 IRC R105.2). Billings requires a permit for decks over 30 in above grade.. Freestanding deck not attached and not over 30 in above grade is generally exempt (2021 IRC R105.2). City or county amendments may apply — verify locally.
🗺️ All projects in Montana
The full Montana permit guide across 20 home projects.
📊 Deck / Porch in every state
Compare the deck / porch rule across all U.S. states.
Deck / Porch in other states
| State | Permit? | Authority | Typical fee | Timeline | Go / No-Go | Key notes |
|---|---|---|---|---|---|---|
| California | Conditional | city | Set by the city — typically a flat fee plus a valuation-based fee. Verify with the city building department. | Same-day Over-the-Counter for low decks (SF); 2–4 weeks elsewhere. | Generally allowed | Attached decks and any deck over 30 in above grade need a permit. SF issues Over-the-Counter permits for decks less than 10 ft above grade that meet setbacks. Exempt: Decks over 30 in (760 mm) above grade require a permit; lower decks are often exempt. |
| Texas | Conditional | city | Set by the city — typically a flat plus valuation-based fee. Verify with the city building department. | 1–4 weeks. | Generally allowed | Attached decks or decks over 30 in above grade require a building permit. Exempt: Decks ≤30 in above grade are exempt (Houston IBC 105.2; Dallas same). |
| Florida | Conditional | city | Set by the city — typically a flat plus valuation-based fee. Verify with the city building department. | 1–4 weeks. | Generally allowed | Attached or raised decks need a building permit. Exempt: Decks >30 in above grade or attached require a permit (FBC R105). |
| New York | Conditional | city | Set by the city — typically a flat plus valuation-based fee. Verify with the city building department. | 1–4 weeks (NYC files through DOB NOW). | Generally allowed | Attached or raised decks need a permit; NYC requires a DOB filing. Exempt: Decks >30 in above grade require a permit (RCNYS R105). |
| Pennsylvania | Permit required | city | Municipal permit fee; Philadelphia EZ Permit available for eligible decks. | Philadelphia EZ Permits reviewed while you wait; standard permits ~15 business days. | Generally allowed | Attached decks and any deck more than 30 in above grade need a permit. Philadelphia offers an EZ Permit for residential decks up to 216 sq ft. |
| Illinois | Permit required | city | Chicago fees via online calculator; other municipalities set their own. | — | Generally allowed | Decks and porches require a permit (Chicago requires permits for decks/porches). Chicago offers an Express Permit for eligible deck work; most other IL towns follow IRC R105. |
| Ohio | Permit required | city | Columbus minimum permit fee $125; total scales with valuation. | Residential permits ~10 business days (Columbus BZS). | Generally allowed | Decks require a permit (Columbus lists deck/ramp permits). Attached decks and any deck more than 30 in above grade always require one. |
| Georgia | Permit required | city | Atlanta minimum permit cost $150 plus $25 technology fee; total scales with construction cost. | — | Generally allowed | Deck/patio additions require a permit (Atlanta lists deck/patio addition). Attached decks and decks over 30 in above grade always require one. |
| North Carolina | Permit required | city | Valuation-based building permit fee; Raleigh uses its Development Fee Guide / calculator. No flat statewide figure. | Plan review commonly 1–3 weeks; Mecklenburg targets ~7 business days for 1–2 family decks. | Generally allowed | Charlotte (Mecklenburg) and Raleigh both require a building permit for any deck/porch regardless of size or height. Footings must reach 12 in below grade; guards required at 30 in+. Exempt: State IRC R105.2 exempts only freestanding decks ≤200 sq ft, ≤30 in above grade, not serving egress — but Charlotte and Raleigh require a permit for ALL decks. |
| Michigan | Conditional | city | Valuation-based building permit; verify with the city. | Typically 5–15 business days; Detroit ~5 days. | Generally allowed | Footings must extend below the frost line — 42 in in the Detroit/Grand Rapids area. Guards required at 30 in+ above grade. Verify setback and lot coverage with the city. Exempt: State R105.2 exempts decks ≤200 sq ft, ≤30 in above grade, not attached, not within 36 in of the dwelling, and not serving egress. |
| New Jersey | Permit required | city | Construction permit based on valuation; plan review fee applies. Verify with the city. | Plan review commonly up to 20 business days; simple permits may be issued sooner. | Generally allowed | New decks require a UCC construction permit and zoning approval; plans by a NJ-licensed design professional are typically required. Newark footings are ~36 in. Repairs to existing decks are exempt if non-structural. Exempt: Newark requires a permit for attached or detached decks over 30 in high; Jersey City requires a permit for any new deck. |
| Virginia | Permit required | city | Building permit based on valuation plus a 2% state levy; verify with the city. | Virginia Beach initial online review targets 3 business days; typical issuance 10–15 business days. | Generally allowed | A building permit is required for new decks (Virginia Beach requires it for every deck, no size/height exemption). Inspections: footing, framing, final. Footings ~18 in in coastal Virginia. Exempt: Prince William: decks with floor ≥16.5 in above grade require a permit. Virginia Beach requires a permit for ALL decks regardless of size/height. |
| Washington | Conditional | city | Valuation-based; fee set by the issuing city. | Simple decks may be Subject-to-Field-Inspection; standard review 4–8 weeks. | Generally allowed | Attached decks and decks over 30 in above grade always require a permit. Exempt: Freestanding decks ≤30 in above grade and ≤200 sq ft are commonly exempt. |
| Arizona | Conditional | city | Valuation-based; Phoenix base building-permit fee is $150. | Over-the-counter or 1–3 weeks depending on complexity. | Generally allowed | Attached decks with a structural ledger connection should be verified with the building department. Exempt: Decks ≤30 in above grade (and not over a basement) are exempt. |
| Massachusetts | Conditional | city | Valuation-based; each city sets its own schedule. | Worcester: ~3–4 weeks; Boston: short-form fast, long-form several weeks. | Generally allowed | A licensed Construction Supervisor (CSL) is required unless the owner does the work on an owner-occupied home. Exempt: Decks ≤200 sq ft, ≤30 in above grade, not attached, not serving a required exit are exempt. |
| Tennessee | Conditional | city | Valuation-based; set by the issuing city/county. | Memphis OCCE ~5–10 business days for standard decks. | Generally allowed | Footing depth follows local frost line (shallow in Memphis, ~12 in Middle TN). Exempt: Decks ≤200 sq ft, ≤30 in above grade, not attached, not serving a required exit are exempt. |
| Indiana | Conditional | city | Set by the local building department. | — | Generally allowed | Attached decks and any deck over 30 in above grade need a permit. Indianapolis requires a structural permit for deck work. Exempt: Decks more than 30 in above grade generally require a building permit under the Indiana Residential Code (IRC R105.2). |
| Missouri | Conditional | city | Permit fees set locally by each municipality — verify with the city building department. | Varies by municipality — over-the-counter/simple permits often same-day to ~2 weeks. | Generally allowed | Kansas City adopted the 2018 IRC (effective 2020); St. Louis enforces the I-Codes locally. Exact thresholds follow local amendments — verify with your city. Exempt: Freestanding decks low to grade and not attached are generally exempt under the locally adopted IRC R105.2; attached decks and decks over 30 in require a permit. |
| Maryland | Conditional | city | Set by the city. | — | Generally allowed | Attached decks and decks over 30 in above grade need a permit. Annapolis publishes deck construction requirements. Exempt: Decks over 30 in above grade generally require a building permit under the IRC (adopted in MD as MBPS). |
| Wisconsin | Conditional | city | Permit fees set by each municipality — verify with the local building inspection department. | Varies by municipality — over-the-counter/simple permits often same-day to ~2 weeks. | Generally allowed | Milwaukee and Madison require a permit for decks attached to the dwelling or over 30 in above grade; footings are inspected for frost depth. Exempt: Freestanding decks low to grade and not attached are generally exempt under the UDC; attached decks and decks over 30 in require a permit. |
| Alaska | Conditional | city | Valuation-based; set by the municipality. | Anchorage initial plan review ~1–3 days; full review longer for complex decks. | Generally allowed | Frost-depth footings are required for every deck — Fairbanks frost depth commonly reaches 60+ in and Anchorage ~40–60 in. Footing inspections occur before concrete is poured. Exempt: Anchorage requires a permit for decks more than 30 in above grade and within 3 ft of grade. |
| Alabama | Conditional | city | Valuation-based; set by the issuing city. | Birmingham residential plan review typically 5–10 business days. | Generally allowed | Birmingham adopts the IBC/IRC with Alabama amendments. Deck footings commonly bottom out at the ~12 in frost depth, but expansive Black Belt clay in central Birmingham often requires deeper footings and a geotechnical report. Exempt: Decks ≤30 in above adjacent grade are typically exempt (IRC R105.2). |
| Arkansas | Conditional | city | Valuation-based; Little Rock minimum building-permit fee $50 (work over $5,000 or requiring inspection). | Little Rock residential plan review typically 5–15 business days. | Generally allowed | Ledger-board attachment is a key inspection point; Arkansas frost line is a mild 12–18 in. Exempt: Decks >30 in above grade or >200 sq ft require a permit (IRC + local); ground-level decks below both are generally exempt. |
| Colorado | Conditional | city | Valuation-based; set by the issuing city/county. | — | Generally allowed | Some cities also require a permit for any deck attached to the house because of the structural connection. Mountain/WUI communities may require fire-resistant decking. Exempt: Most Colorado cities require a permit for decks >30 in above grade or >200 sq ft; ground-level decks below both are generally exempt. Denver and Colorado Springs follow IRC thresholds. |
| Connecticut | Conditional | city | Valuation-based; set by the city/town. | — | Generally allowed | Ledger-board attachment is a key inspection point. Exempt: Decks >30 in above grade require a permit (IRC R105.2); attached or higher decks require a permit. |
| Delaware | Conditional | county | Valuation-based; set by the county or city. | — | Generally allowed | Ledger-board attachment is a key inspection point. Exempt: Decks >30 in above grade require a permit (IRC); attached or higher decks require a permit (Kent County follows the 2018 IRC). |
| Hawaii | Conditional | county | Valuation-based; set by the county building department. | Plan review for permitted decks; over-the-counter for simple low platforms where exempt. | Generally allowed | All structural lumber above ground must be preservative-treated for Formosan termite resistance per Hawaii’s amended code; wind-load design (105–170 mph gusts by location) applies. Verify with the county building department. Exempt: Platforms, walks, and driveways not more than 30 in above grade and not over a basement are exempt. |
| Iowa | Conditional | city | Valuation-based; set by the issuing city. | Over-the-counter to a few weeks depending on complexity. | Generally allowed | Attached decks and any deck above 30 in require a permit and footings below the local frost line (36-42 in across Iowa). Exempt: Freestanding decks 30 in or less above adjacent grade are typically exempt. |
| Idaho | Conditional | city | Valuation-based; set by the issuing city. | Over-the-counter or plan review depending on complexity. | Generally allowed | Attached decks with a structural ledger connection should be verified with the building department; mountain areas require local snow-load design. Exempt: Decks ≤30 in above grade (not serving as an exit) are exempt under the Idaho Residential Code. |
| Kansas | Conditional | city | Valuation-based; set by the issuing city. | Wichita 5-10 business days typical. | Generally allowed | Footings must extend below the local frost line (24-36 in across Kansas). Exempt: Overland Park requires a permit for all new/replacement decks; Wichita requires a permit for decks over 30 in above grade. |
| Kentucky | Conditional | city | Valuation-based; set by the issuing city. | Lexington simple decks can be approved same-day if filed before 4 p.m. | Generally allowed | Attached decks and any deck above 30 in require a permit; footings below the local frost line (about 24 in in Lexington). Exempt: Freestanding decks 30 in or less above grade are typically exempt under the KRC (2015 IRC). |
| Louisiana | Conditional | city | Valuation-based; set by the issuing parish/city. | NOLA residential renovation permits 2-5 business days. | Generally allowed | Attached or elevated decks require a permit and wind/hurricane detailing. Exempt: NOLA exempts uncovered decks <=200 sq ft and <=30 in high, not attached, not serving as an exit. |
| Maine | Conditional | city | Valuation-based; set by the issuing municipality (no statewide flat fee). | 1–4 weeks for plan review; simple exempt work is over-the-counter. | Generally allowed | Maine uses a 200 sq ft deck exemption (higher than the base IRC 120 sq ft). Footings must reach the local frost depth (commonly 48–60 in). Attached decks need a permit even if small — confirm with the Code Enforcement Officer. Exempt: Freestanding decks ≤200 sq ft and ≤30 in above grade are exempt. |
| Minnesota | Conditional | city | Permit fees set by the municipality; verify locally. | Varies by municipality — simple decks often same-day to a few weeks. | Generally allowed | Minnesota has deep frost depths (roughly 42 in across the Twin Cities) — deck footings must extend below the local frost line. Verify with Minneapolis Development Review or Saint Paul DSI. Exempt: Freestanding decks low to grade and not attached are generally exempt; attached decks and decks over 30 in above grade require a permit. |
| Mississippi | Conditional | city | Where enforced, fees follow the local schedule (e.g., Jackson scales with valuation). Verify locally. | Varies by jurisdiction. | Generally allowed | If your jurisdiction does not enforce a building code, no structural permit is required. The six coastal counties must enforce coastal wind/flood provisions. Exempt: Where a code is enforced (e.g., Jackson adopts the 2018 IRC), a freestanding deck not over 30 in above grade and under ~200 sq ft is typically exempt. |
| North Dakota | Conditional | city | — | — | Generally allowed | Footings must extend below ND frost depth (commonly 48–60 in depending on region). Ledger flashing and guardrail details are reviewed. Check with your local building department. Exempt: State code (IRC R105.2) exempts decks ≤200 sq ft, ≤30 in above grade, not attached, not serving the exit door. |
| Nebraska | Conditional | city | Permit fees set by the municipality; verify locally. | Varies by municipality — simple decks often same-day to a few weeks. | Generally allowed | Nebraska adopts the 2018 IRC (R313 sprinklers and chapters 25-33 mechanical/plumbing replaced by state codes). Deep frost depths (about 42 in in Omaha/Lincoln) set footing requirements. Verify locally. Exempt: Freestanding decks low to grade and not attached are generally exempt; Omaha permits decks over 30 sq ft or more than 30 in above grade, and Lincoln requires a permit for all decks. |
| New Hampshire | Conditional | city | — | — | Generally allowed | New Hampshire footings must extend to frost depth (commonly 48 in). Even exempt low decks must meet zoning setbacks. Verify the threshold with your local building department — some towns permit any attached deck. Exempt: Decks ≤30 in above adjacent grade and (in most towns) ≤200 sq ft are exempt from a building permit. |
| New Mexico | Conditional | city | — | — | Generally allowed | Setbacks and lot-coverage limits still apply. In LEAs like Albuquerque, plan review typically takes 10–15 business days; Santa Fe historic-district properties need additional design review. Exempt: Decks ≤200 sq ft, ≤30 in above grade, not attached to the dwelling, and not serving the required exit door are exempt. |
| Nevada | Conditional | city | Valuation-based; Reno offers flat-rate EZ permits for simple decks. Clark County fees scale with valuation. | Over-the-counter/EZ for simple decks; plan review for attached or elevated decks. | Generally allowed | Attached decks with a structural ledger connection and any deck above 30 in require a permit and footing inspections (frost depth matters in Washoe County). Exempt: Decks ≤30 in above adjacent grade (not over a basement) are exempt from a building permit per IRC R105.2 / Clark County exemption. |
| Oklahoma | Permit required | city | Valuation-based; OKC deck permits are commonly a few hundred dollars per the city fee schedule. | OKC: simple decks often approved within 5–10 business days; over-the-counter for some. | Generally allowed | Oklahoma’s tornado-wind design speeds (≈105–135 mph) drive hold-down hardware, post anchorage, and continuous load path; expansive-clay soils require deeper/larger footings. Exempt: IRC R105.2 exempts decks ≤30 in above grade, but OKC requires a permit for any attached deck and for detached elevated decks regardless of size. |
| Oregon | Conditional | city | Valuation-based; Portland permit fees follow the city building-permit fee schedule. | Over-the-counter for low decks; plan review for elevated decks. | Generally allowed | Oregon’s seismic-active status means deck ledger and connection details are inspected; footnote to local frost/soil conditions. Exempt: Porches/decks ≤30 in above adjacent grade are exempt (statewide). Portland: decks/stairs >30 in above grade require a permit. |
| Rhode Island | Conditional | city | Rhode Island statewide valuation-based fee formula (Providence minimum permit fee $125). | Over-the-counter for low decks; plan review for elevated decks (Providence ~3 weeks for decks >200 sq ft). | Generally allowed | Coastal/glacial soils and a 42 in frost depth mean deck footings must be inspected for depth. Exempt: Decks ≤30 in above adjacent grade are exempt (RI follows IRC R105.2). |
| South Carolina | Conditional | city | Valuation-based; Charleston adds an application + zoning-review fee on top of the permit fee. | Plan review ~2–3 weeks (Charleston); footing inspection before concrete. | Generally allowed | Coastal South Carolina design wind speeds reach 130–160 mph (Wind-Borne Debris Regions); hurricane-rated hardware and flood-zone elevation rules often apply. Exempt: S.C. Code § 40-59-265 exempts decks NOT exceeding 200 sq ft AND not more than 30 in above grade at any point. |
| South Dakota | Conditional | city | Valuation-based; set by the issuing city. | Over-the-counter or 1–3 weeks depending on complexity. | Generally allowed | Sioux Falls footings must extend to the local 42-inch frost depth; verify with the building department before sizing footings. Exempt: Decks ≤30 in above adjacent grade are exempt under IRC R105.2. |
| Utah | Conditional | city | Valuation-based; set by the city. | Over-the-counter or 1–3 weeks depending on complexity. | Generally allowed | Utah amendments emphasize proper ledger-board attachment, flashing, and lateral-load connections for decks. Exempt: Decks ≤30 in above adjacent grade are exempt under IRC R105.2. |
| Vermont | Conditional | city | Valuation-based where enforced. | Over-the-counter or 1–3 weeks where enforced. | Generally allowed | Vermont frost depth runs 48–60 in; deck footings must extend below the local frost line. Snow loads 40–70 psf apply. Exempt: Decks ≤30 in above adjacent grade are exempt under IRC R105.2. |
| West Virginia | Conditional | city | Valuation-based; fees waived for total job cost ≤ $2,500. | Over-the-counter or 1–3 weeks depending on complexity. | Generally allowed | Charleston issues permits for decks; follow the state code footing/frost and guardrail requirements. Exempt: Decks ≤30 in above adjacent grade are exempt under IRC R105.2. |
| Wyoming | Conditional | city | Valuation-based where enforced. | Over-the-counter or 1–3 weeks depending on complexity. | Generally allowed | Cheyenne footings must address high wind and deep frost; verify with the building department. Exempt: Decks ≤30 in above adjacent grade are exempt under IRC R105.2. |