Research by DoINeedAPermit Research Team · Updated May 2026
The Short Answer
Yes. Any deck attached to your house requires a permit in Rexburg, regardless of size or height. Rexburg Building Department enforces IRC R507 and requires structural review for ledger attachment, footings below frost depth, guardrails, and stairs.
Rexburg's Building Department adopts the International Residential Code (IRC) as its baseline but amplifies structural requirements because of the city's extreme frost depth (24-42 inches in the Palouse loess soils of the Bannock County region). Unlike some neighboring Idaho communities that exempt small ground-level decks under 200 square feet, Rexburg treats ANY attached deck as a structural modification and requires full plan review. The city's online permit portal (accessible through the Rexburg city website) requires sealed stamped plans from a designer or engineer for decks over 120 square feet or over 30 inches high; smaller attached decks can sometimes use prescriptive (non-stamped) plans if the applicant meets strict detail requirements. Ledger flashing and footing depth are the two highest-rejection reasons here because the frost line forces footings 36-42 inches deep in most of the city, and flashing must slope away from the house per IRC R507.9. Plan review typically takes 2-3 weeks. Electrical or plumbing on the deck (hot tub, outdoor kitchen) triggers additional MEP review.

What happens if you skip the permit (and you needed one)

Rexburg attached deck permits — the key details

Rexburg Building Department enforces the 2020 International Residential Code (IRC), with local amendments that emphasize frost depth and soil conditions. IRC R507 governs all residential decks and requires every attached deck to have a ledger board bolted to the house rim joist with bolts spaced 16 inches on center, rated for lateral load (Simpson LUS210 or equivalent). The ledger must be protected with metal flashing that slopes away from the house per IRC R507.9, and that flashing detail is the single most common reason decks fail first inspection in Rexburg. Footings must rest below the maximum frost line in your area — in Rexburg that is typically 36-42 inches depending on the exact soil type and neighborhood (City Hall can confirm for your specific address). Posts must be 6x6 minimum (or two 2x6s sistered) for spans over 8 feet, and beam-to-post connections must use approved hardware (Simpson U210 straps or equivalent bolted connections, not nails or screws). Guardrails are required if the deck is over 30 inches above adjacent grade and must be 36 inches high (measured from the deck surface to the top rail), with balusters spaced no more than 4 inches apart to prevent a sphere test failure. Stairs must have treads of 10-11 inches, risers of 7-7.75 inches, and at least one handrail if there are four or more steps; landing depth under the stairs must be at least 36 inches.

Rexburg's specific challenge is the Palouse loess and Snake River Plain volcanic soils, which are prone to frost heave and, in some neighborhoods, expansive clay. This is why the city requires footing depth certification; a standard backhoe excavation to 42 inches must be photographed and inspected by the Building Department before concrete pour. If your deck is on a corner lot or near the Rexburg airport (noise overlay), or if it's in a historic district (downtown core), additional reviews or deed restrictions may apply. The Building Department's online portal (accessible via the city website under 'Permits') allows you to upload plans digitally, but you must create a municipal account first. Attached decks do not require a survey unless the deck encroaches within 5 feet of a side or rear property line; if you're near a line, a surveyor ($300–$600) can clarify and is cheaper than a rejected permit. Owner-builders are allowed in Rexburg for owner-occupied single-family dwellings, so you may pull the permit yourself and do the work, but you must still submit sealed plans for decks over 120 square feet.

Plan preparation and submission: if your deck is under 120 square feet and under 30 inches high, you can sometimes use the City's prescriptive plan sheet (available from the Building Department) and avoid a stamp. For anything larger or higher, you need a designer or engineer to produce a sealed plan showing footing depth, ledger detail with flashing, post sizing, beam sizing, railing detail, and stair detail. Rexburg Building Department recommends submitting one copy printed and one digital PDF via the portal. Review turnaround is typically 2-3 weeks; the Department emails you a 'Plan Review Comments' sheet listing required changes or approvals. Once approved, you receive a permit letter and a job card; this is your authorization to begin work. You then schedule a footing pre-pour inspection (required before concrete), a framing inspection (after posts, beams, and ledger are set), and a final inspection (after stairs, railing, and flashing are complete). Each inspection costs $50–$75 and is bundled into your permit fee.

Fees and timelines: Rexburg permit fees for attached decks are based on estimated project valuation (material + labor). A typical 16x12 deck (192 sq ft) with stairs and railing costs about $8,000–$12,000 to build; the permit fee is roughly 2.5-3% of valuation, so $200–$360. A larger 20x16 deck (320 sq ft) with electrical run-in for a hot tub or outdoor kitchen may trigger a $400–$500 permit. Fees are non-refundable once the permit is issued. Plan review, inspections, and final approval typically take 3-4 weeks from submission if you provide complete and compliant plans on the first round. If the Building Department finds deficiencies, you revise and resubmit, which adds another 1-2 weeks. Electrical work (outlet on the deck, hot tub wiring) requires a separate electrical permit and a licensed electrician; plumbing for an outdoor sink or spa also requires separate MEP permits and inspections.

Post-approval: once your final inspection is signed off, the Building Department issues a Certificate of Occupancy or 'Work Completed' letter. Keep this with your house records — you'll need it for refinance, resale, or insurance claims. If you're financing the deck with a home-equity loan or HELOC, your lender may require proof of permit and final inspection before disbursement. Rexburg's Building Department also flags unpermitted structures during code-enforcement sweeps (especially in spring when decks are visible), so a permitted deck protects you from neighbor complaints or municipal enforcement actions. If you ever plan to sell, the final permit letter becomes part of your disclosure package and actually adds confidence to a buyer.

Three Rexburg deck (attached to house) scenarios

Scenario A
12x14 attached deck, 18 inches above grade, composite decking, no electrical — North Rexburg residential zone
You're building a modest 168-square-foot composite deck attached to the east side of your house in a typical North Rexburg neighborhood (loess soil, standard frost depth ~36 inches). The deck is only 18 inches above grade, so guardrails are not required (IRC R107 exempts decks under 30 inches). However, because it is attached to your house, you absolutely need a permit. Your plan requirements are minimal: a simple 1/4-inch scale drawing showing the house footprint, the deck footprint, the ledger detail with flashing sloped away, and footing locations with depth marked (36 inches minimum). The ledger must be bolted to your rim joist with 1/2-inch bolts every 16 inches. Posts can be 4x4 (composite or treated lumber) set in concrete footers below frost depth. You will not need a sealed engineer's plan because the deck is under 200 square feet and under 30 inches high; Rexburg allows prescriptive plans for this scope. Submit your sketch-plan via the online portal (or in person at City Hall, 20 West Main Street) with a $65 application fee. Review takes 1 week. Once approved, you schedule a footing pre-pour inspection (photo inspection on-site), then pour concrete, then frame and deck. Framing inspection follows (post connections, ledger bolts, decking fastening), and final inspection checks flashing, ledger trim, and any ground settlement. Total permit cost is $200–$250 including all inspections. Timeline: submit to approval (1 week), construction (2-3 weekends), final inspection (1 day). You can do this work yourself as an owner-builder.
Attached to house so permit required | Prescriptive plan allowed (≤168 sq ft) | 4x4 posts in 36-inch footers | Ledger bolts 16 inches on center | Footing pre-pour inspection required | Framing and final inspections | Permit fee $200–$250 | 1-week plan review
Scenario B
20x16 two-tier deck with stairs, 42 inches at high end, fibreglass deck boards, hot tub electrical outlet — South Rexburg near golf course (expansive clay soil overlay)
You're building a 320-square-foot multi-level deck with a 12-step staircase down to a lower 8x12 platform on a South Rexburg lot within a mapped expansive clay zone (per Bannock County soil survey). The upper deck is 42 inches above the lower grade, so full guardrails (36 inches high, 4-inch baluster spacing) are required on all open sides. Because the deck exceeds 120 square feet and exceeds 30 inches in height, Rexburg Building Department requires a sealed plan from a licensed engineer or architect (not a prescriptive plan). Your engineer must show: footing locations and depths (your lot's expansive clay requires geotechnical sign-off, adding $400–$600 for a soil report), post and beam sizing (likely 6x8 beam on 6x6 posts in this case), ledger flashing detail per IRC R507.9, stair stringers and landing dimensions (36-inch minimum landing depth under and in front of the staircase), guardrail details (36-inch height, Simpson G-1 or similar railing connectors), and the deck's lateral load tie-in (Simpson LUS210 ledger straps every 16 inches). You also need an electrical permit from a licensed electrician to run an outlet to the hot tub location (separate from the deck permit, but coordinated). Submit your sealed plans via the Rexburg portal along with the soil report and a $45 application fee. The Building Department's structural engineer reviews for 2-3 weeks (longer because of the soil complexity and tie-in with expansive clay mitigation). Once approved, footing inspection is critical — the inspector will verify that all footers are below the frost line (36-42 inches) and that any expansive clay mitigation (geotextile, gravel pad, pier-and-beam system) is in place per the soil report. Framing inspection checks post-to-beam bolting, ledger bolts, stair stringer lag bolts to the house, and landing dimensions. Final inspection verifies guardrail height, baluster spacing (sphere test), stair tread/riser dimensions, flashing completion, and the electrical outlet rough-in. Total permit cost: deck permit $450–$500, electrical permit $75–$100. Timeline: soil report and engineer plan (2 weeks), permit review (2-3 weeks), construction (4-5 weeks), inspections (3 days spaced across construction). This project requires a licensed contractor or very experienced owner-builder.
Sealed engineer plan required (≥120 sq ft + ≥30 in height) | Expansive clay soil report required ($400–$600) | 6x6 posts 36-42 inches deep | 6x8 beam on post pairs | Ledger flashing SBS detail with bolts 16 inches on center | Stairs with 10.5-inch treads, 7-inch risers | Guardrail 36 inches, 4-inch baluster spacing | Hot tub electrical permit (separate, $75–$100) | Deck permit $450–$500 | 2-3 week structural review
Scenario C
8x10 freestanding platform deck, 24 inches above grade, attached beams touching house siding (not bolted), no stairs — Central Rexburg lot near historic district boundary
You want to build a modest 80-square-foot elevated platform next to your house in Central Rexburg. You're thinking 'freestanding' to avoid the ledger hassle, but your beams will sit within 12 inches of the house siding for aesthetics and to minimize cold air underneath. Here's the trap: if the deck is attached to the house (even just touching the siding, even if not bolted), it is classified as an attached deck and requires a permit. If the beams are truly free-standing and do not bolt or attach to the house rim joist or foundation in any way, AND the deck is under 30 inches high AND under 200 square feet, it may qualify as exempt under IRC R105.2. However, Rexburg's interpretation is strict: if the deck is placed so close to the house that it looks integrated, inspectors often require a permit 'to be safe' and to document the separation. We recommend pulling the permit; the alternative is a code-enforcement stop-work order during your first inspection by a neighbor or city drive-by. With the permit, you submit a simple plan showing the deck as free-standing (footings are 24 inches away from the house siding, not touching). You set four 4x4 posts in 36-inch frost-line footings on concrete pads, attach a rim board, add 2x8 joists, and install composite decking. No ledger, no stairs, no railings (because 24 inches is under the 30-inch threshold). Plan review is 1 week; inspection is a simple footing and post pre-pour (1 visit), framing (1 visit), and final (1 visit). You can use a prescriptive plan (sketch provided by the city) or submit your own 1/4-scale drawing. Total permit fee is $150–$200. However, if you're near the historic district boundary (roughly Main Street to Hill Road in Central Rexburg), the Historic Preservation Commission may require design review of the deck's visibility and materials (no bright plastic, muted colors preferred); this adds 2-3 weeks to the process. Timeline: submit plan (1 day), review (1-2 weeks depending on historic review), inspections (1-2 weeks), final (1 day). Total project timeline 4-5 weeks.
Attached by proximity, permit required | Freestanding post design (4 footers, 36 inches deep) | 4x4 posts, pressure-treated lumber | No ledger flashing required | No guardrails (24 in < 30 in threshold) | No stairs | Prescriptive plan allowed | Permit fee $150–$200 | Historic district review may add 2-3 weeks

Every project is different.

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Frost depth and footing failure: why Rexburg's 36-42 inch requirement matters

Rexburg sits in the heart of the Palouse loess region and the Snake River Plain volcanic zone, both of which experience severe winter frost heave. Frost heave occurs when water in the soil freezes, expands, and lifts structures built on shallow footings. Rexburg's frost line reaches 36-42 inches in most neighborhoods; this means that soil freezes solid to that depth every winter. If your deck footings rest above that line (say, only 24 inches deep), the frozen soil will push upward on your posts by 2-4 inches each winter, and thaw settlement will drop them back down in spring. Over 3-5 years, this cycle causes the deck to rack (twist), the ledger to separate from the house, and guardrails to fail.

The Rexburg Building Department requires footing depth certification because of this local hazard. Before you pour concrete, the inspector visits the excavation, measures the hole depth, photographs it, and confirms the bottom is at or below frost depth. Some inspectors also require a soil observation to rule out expansive clay or other problem soils; if expansive clay is found, a geotechnical report may be needed. This is not bureaucratic theater — it is the difference between a 20-year deck and a failed deck in year five.

If your lot is in a flood zone (Rexburg has some FEMA zones near the Teton River and creeks), frost depth may be deeper (up to 48 inches) because colder soil near water bodies freezes further. The city's flood map is available at the Building Department or online via the FEMA Flood Map Service Center. If you're unsure of your frost depth, call the Building Department and provide your address; they can confirm the requirement for your specific neighborhood.

Ledger flashing and attachment: the number-one Rexburg deck failure

IRC R507.9 requires the ledger board (the beam that attaches your deck to your house) to be bolted to the house's rim joist (the outer beam that sits atop your foundation) and protected with flashing. The flashing is a metal Z-channel or L-channel that sits behind the rim board's exterior sheathing and slopes downward and outward away from the house. The purpose is to shed water away from the rim board and house rim, preventing rot, ice dams, and water intrusion into your house rim and foundation. Rexburg's cold-wet climate (snowmelt and rain) makes this detail critical; rim boards and rims are the weak point for water damage.

Common Rexburg rejections: flashing missing entirely (rim-flash bolted directly to siding); flashing installed upside-down or sloped inward (water runs into the rim); flashing not extended far enough down the rim; flashing not sealed with sealant at the ledger-to-flashing joint; bolts corroded or undersized; bolts spaced more than 16 inches on center (should be 16 inches or closer). The fix is always to remove the ledger, install proper flashing per the manufacturer's detail (Simpson, Fortress, etc.), re-bolt with new bolts, and re-seal. This adds $800–$2,000 in labor and can delay your final inspection by 2-3 weeks.

To pass first inspection, get your engineer's or designer's flashing detail in writing on your sealed plan. Specify the flashing product by name and dimension (e.g., 'Simpson LUS210 ledger tie with 20-gauge galvanized flashing'). Show the slope direction in a cross-section. Install the flashing before the deck board, not after. Schedule your framing inspection only after the ledger is fully flashed and bolted, and take a photo of the detail before the inspector arrives — this helps speed the review. Rexburg inspectors are thorough and will reject any detail that does not match IRC R507.9 exactly.

City of Rexburg Building Department
City Hall, 20 West Main Street, Rexburg, ID 83440
Phone: (208) 359-3000 (main line; ask for Building Department) | https://www.rexburg.org (navigate to 'Permits' or 'Building Department' for online portal access)
Monday–Friday, 8:00 AM–5:00 PM (verify locally before visiting)

Common questions

Do I really need a permit if my deck is only 12 feet away from the house and not bolted to it?

If the deck is truly free-standing (no bolts, no attachments to the house at all, more than 18 inches from the siding), and it is under 30 inches high and under 200 square feet, it may be exempt under IRC R105.2. However, Rexburg Building Department inspectors often require a permit anyway if the deck is placed close to the house for 'clarity and safety.' Our recommendation: pull the permit if the deck is within 24 inches of the house. It costs $150–$200 and prevents a stop-work order.

What if I hire a contractor — do they handle the permit, or do I?

Most contractors in Rexburg will pull the permit as part of their bid and include the permit fee in the contract price. Ask your contractor explicitly: 'Are you pulling the permit, or am I responsible?' Once the permit is issued, the contractor is responsible for scheduling inspections and ensuring the work meets code. You remain the responsible party for the permit, so sign the application yourself and keep a copy for your records.

How deep do I have to bury the footings in Rexburg?

Footings must rest below the frost line, which is 36-42 inches in Rexburg depending on the specific neighborhood and soil type. The City of Rexburg and Bannock County can confirm the exact depth for your address. Some neighborhoods with expansive clay soils (South Rexburg near the golf course, some areas near the airport) may require deeper or special pier-and-beam systems; call the Building Department to confirm before you excavate.

Can I use pressure-treated lumber for the entire deck, including posts, or do I need composite?

Pressure-treated lumber (UC4B or better for ground contact) is code-compliant and cheaper than composite for posts and beams. Rexburg does not require composite. Use pressure-treated 4x4 or larger for posts and 2x8 or larger for beams. Composite or treated lumber is fine for deck boards; composite is more durable in Rexburg's cold-wet climate and does not rot. Untreated lumber is not allowed for any ground-contact or weather-exposed members.

If I'm building on expansive clay soil, does that change my permit cost or timeline?

Yes. Expansive clay soils (common in South Rexburg and some neighborhoods near the airport) require a geotechnical soil report ($400–$600) before the Building Department will approve footings. This adds 1-2 weeks to the permit review timeline and increases your overall project cost. Your engineer will specify special footing details (geotextile, gravel pads, or deeper footings) based on the soil report. Ask the Building Department if your address is in a mapped expansive soil zone.

What is the typical wait time for a footing pre-pour inspection in Rexburg?

Footing inspections in Rexburg are typically scheduled within 2-3 business days of your request. You call the Building Department (208) 359-3000, provide your permit number, and request an inspection date. The inspector meets you on-site, verifies the footing depth, takes photos, and issues a pass or fail on the spot. Plan ahead: don't call for an inspection if you're expecting rain (footing holes fill with water) or if it's below 32 degrees and the ground is frozen.

My neighbor says my deck is too close to his property line. Does the city care?

Yes. Rexburg code requires decks to be set back from side and rear property lines (typically 5-10 feet depending on zoning). If your deck is within 5 feet of a neighbor's line, you may need a survey ($300–$600) to verify the property boundary. If the deck actually encroaches on the neighbor's property, it must be relocated or removed. Resolve this before you submit your permit — the Building Department will ask for proof of line compliance, and a survey or deed reference is the quickest way to prove it.

If I'm adding electrical (outlet or lights) to the deck, is that a separate permit?

Yes. Outdoor electrical work (outlets, lights, hot tub wiring) requires a separate electrical permit and must be done by a licensed electrician. The electrical permit is roughly $75–$150 and is handled by Rexburg's Building Department along with the deck permit. Coordinate with your electrician: the electrical rough-in (conduit, boxes) is usually inspected before the deck is fully boarded, so the inspector can access the wiring.

What happens if I build the deck without a permit and then try to sell my house?

During the home sale inspection and appraisal, an unpermitted deck is flagged. Your title company and lender will require either (1) retroactive permit and final inspection (add 4-6 weeks and $300–$500), or (2) a signed engineer's letter stating the deck is code-compliant. Many sellers end up doing demolition instead ($2,000–$5,000 labor). Unpermitted decks also raise red flags for insurance claims and refinance. It is far easier and cheaper to pull the permit upfront.

Does Rexburg require a survey before I pull a deck permit?

A formal survey is not required unless your deck is within 5 feet of a side or rear property line, or if the property line is unclear from the deed. If you're confident the deck is well within your property, you do not need a survey. However, if a neighbor objects or the Building Department asks for proof of line compliance, a surveyor can verify boundaries quickly. A survey runs $300–$600 and is cheaper than a permit rejection or deck relocation.

Disclaimer: This guide is based on research conducted in May 2026 using publicly available sources. Always verify current deck (attached to house) permit requirements with the City of Rexburg Building Department before starting your project.