What happens if you skip the permit (and you needed one)
- Stop-work order: City inspector finds unpermitted deck, issues a stop-work order ($250 fine) plus demand to remove or obtain retroactive permit with double fees ($400–$900 total).
- Insurance denial: Homeowner's insurance may deny a claim on deck collapse or water damage to the house if the ledger flashing was not permitted and inspected; typical denial costs $15,000–$50,000 in uninsured repair.
- Resale title issue: Unpermitted deck triggers a disclose-defect notice to future buyer; many buyers walk, or demand $10,000–$25,000 credit to cover removal or retroactive permitting.
- Lender/refinance block: If you refinance or get a home equity line, lender's title company flags unpermitted work; line of credit denied or work must be removed before closing.
Midvale attached-deck permits — the key details
The single most important rule in Midvale is ledger-board flashing and attachment. IRC R507.9 requires a moisture barrier (typically self-adhering flashing tape or metal flashing) behind the ledger board to prevent water from seeping between the house rim board and the deck ledger—water that will rot the house frame within 3–5 years and can cause structural failure. Midvale's building inspector will ask for a detail drawing of the flashing: where it sits relative to the rim board, where siding is removed, how it laps over the house's moisture barrier, and how it's fastened. Many homeowners and even some deck builders skip this or do it wrong (tape only, no metal; flashing not extended down to the foundation; fasteners placed where water can pool). The city's plan-review checklist explicitly requires IRC R507.9 compliance with a detail drawing showing the ledger at the rim-board elevation, flashing lapped onto house sheathing, and clearance between deck surface and house siding. If your plan lacks this detail or shows a non-compliant flashing design, the city will issue a comment ('request for information,' or RFI) and hold the permit until you resubmit. This adds 1–2 weeks to your timeline.
Frost-depth footings are the second major hurdle. Midvale sits in climate zone 5B (Wasatch foothills) to 6B (higher elevations), with frost depth of 36–48 inches depending on exact location and elevation. Utah Code (adoption of IRC R403.1) requires all footings to extend below the frost line to prevent heave—the upward push of freezing soil that can lift deck posts and creak ledger connections over winter. The Midvale Building Department's typical comment on footing details is 'Extend all footings to 48 inches below final grade' or 'Show frost-depth certification for your specific lot.' If your deck plan shows 36-inch footings and your lot is in the high-frost zone, the city will flag it. You'll need either to go to 48 inches or to provide a soils engineer's letter certifying your actual frost depth. Some builders try to argue that a stone base or frost blanket saves depth—the city will reject that. Excavate deep and stay compliant. The $15–$30 cost difference per footing post is trivial compared to jacking the deck later.
Seismic bracing and lateral load connections are increasingly scrutinized in Midvale because the city is within 10–15 miles of the Wasatch Fault, a major seismic hazard. The 2021 Utah Code (IBC Table 1613.5) places Midvale in seismic design category D1, meaning deck framing must include lateral bracing. Specifically, IRC R507.9.2 requires post-to-beam connections that resist shear and lateral forces—typically Simpson Strong-Tie LUS210 or equivalent post bases that include both vertical and lateral load devices. If your plan shows simple bolts or bolts plus a metal bracket that only handles vertical load, the city will ask for an upgraded connection detail showing lateral capacity. This usually means a $50–$150 upgrade per post (two posts minimum for most decks). Also, if your deck spans perpendicular to the house and is more than 12 feet wide, the city may require bracing of the outer beam against lateral sway—diagonal bracing or an engineer-stamped analysis. This is a surprise cost for many homeowners, but it's real and required.
Expansive-soil settlement is a Midvale-specific issue. The city sits on Lake Bonneville clay and silt deposits, which swell when wet and shrink when dry. If your lot is on a slope or near irrigation or landscaping, clay settlement and heave can be 1–2 inches over a few years. The city doesn't typically require a soils test for a standard residential deck (that would be overkill), but if your footing excavation reveals clay, the inspector may ask for underdrained footings (a 4-inch gravel bed under the post, draining away) or a note that you're aware of the soil type. Some engineers recommend a geotextile fabric under the gravel to prevent clay fines from mixing back in. This is a 'nice to know' rather than a deal-breaker for the permit, but it's worth mentioning in your plan notes.
The permit process itself in Midvale runs 2–3 weeks from submission to approval (not including any RFIs). The city allows online portal submission (via the Midvale city website) or in-person filing at City Hall. Typical fees are $200–$450 depending on the assessed value (city uses a valuation formula of roughly 1.5–2% of construction cost, plus $50–$100 base fee). Once you have your permit, inspections are required at three stages: footing pre-pour (inspector verifies depth and setback before concrete), framing (after ledger is attached and beams are set), and final (railings, stairs, electrical if any). Each inspection can be scheduled online or by phone; typical turnaround is 1–2 business days. If the inspector finds a defect (e.g., footings not deep enough, ledger not flashed), you'll get a written deficiency notice and have 30 days to correct and request re-inspection. Plan for 4–6 weeks total from permit issuance to final sign-off.
Three Midvale deck (attached to house) scenarios
Frost depth and expansive soil in Midvale: why 48 inches matters
Midvale sits in USDA Hardiness Zone 5B to 6B, depending on elevation. The Wasatch Valley floor (where most of Midvale is) hits a 36–40 inch frost depth; higher elevations (foothills) can reach 48 inches. This is not a guess—the city and Utah Building Science Lab have surveyed frost depth over decades, and the current 2021 Utah Code (IBC Section 1809.5 / IRC Table R403.1) specifies that all footings must rest below the frost line. Why? When soil freezes, it expands (ice lenses form in clay and silt, pushing upward). If a deck post footing sits above the frost line, the post will heave upward 1–3 inches each winter and sink back when soil thaws. Over five years, this creates a rocking motion that cracks the ledger connection and loosens bolts, eventually causing the deck to separate from the house. The ledger then becomes a drainage point—water pools and rots the rim board, leading to structural failure. Inspectors in Midvale are trained to look for heave damage in existing decks and will not approve new decks with shallow footings. If your footing plan shows 36 inches and your lot is in the higher-frost zone, the city will ask for 48 inches or a geotechnical engineer's report justifying the 36-inch depth (rare approval). The cost difference is minimal: an extra 12 inches of excavation is roughly $20–$50 per post, plus maybe 50 cents in concrete. This is not worth fighting.
Expansive soil is a secondary but real concern. Lake Bonneville clay (the dominant soil under Midvale) has a Potential Vertical Rise (PVR) of 2–4 inches if fully saturated, dropping to 0.5–1 inch in typical seasonal moisture variation. Deck footings sitting on clay can settle 1/2 inch to 1 inch over a few years, especially if irrigation or landscape changes increase moisture. Unlike heave, settlement doesn't crack anything directly, but it can cause uneven deck settling (one corner drops more than another), creating slopes and stress on the ledger. The building inspector doesn't require a soils test for residential decks, but you can request one ($500–$1,200) if you want certainty. More practical: if you're digging post holes and hit clay at 4 feet, place a 4-inch gravel bed under each footing (as an underdrain), cover with geotextile fabric, then pour the footing concrete. This gives clay time to drain and reduces settlement. Cost: roughly $20–$50 per footing, money well spent on a Midvale clay lot.
The city's inspection process focuses on frost depth verification. The footing pre-pour inspection is the critical moment: an inspector will visit your job site as you're about to pour concrete and will measure the hole depth with a tape measure or depth gauge. If you've excavated to 42 inches but your plan said 48, the inspector will stop the pour and ask for the extra 6 inches. You can't pour and ask forgiveness. Many homeowners hire an expediter or contractor familiar with Midvale's standards to ensure pre-pour compliance, adding $150–$300 to the project but avoiding delays.
Ledger flashing and moisture protection: the #1 reason Midvale decks fail
Water intrusion at the ledger is the leading cause of deck failure in Utah, and Midvale inspectors have seen it countless times. The ledger board is the 2x10 or 2x12 rim member bolted to the house's rim board (the outer edge of the floor frame). Between the deck ledger and the house rim, there's a potential gap—even if bolted tight, capillary action wicks water into the wood joint. This water rots the house's rim board, band board, and rim joist within 3–5 years if unprotected. IRC R507.9 requires moisture protection at the ledger: specifically, a continuous water-resistive barrier (WRB) that sheds water away from the house. The standard detail in Midvale shows: siding is removed for 12 inches above the ledger and 12 inches below the ledger-bolts line; self-adhering flashing tape (3M 8067 or equivalent) is applied to the house's rim-board sheathing; the tape is lapped upward so that house's WRB overlaps the top of the tape and sheds water outward; then a metal flashing (typically L-shaped aluminum or galvanized steel, 2 inches up x 2 inches out) is installed on top of the tape, also lapping upward into the house's WRB. The ledger is then bolted through the flashing and tape into the rim board, and siding is replaced, covering the top of the flashing. This creates a shed that forces water down and out, away from the joint.
The city's plan-review process requires a detail drawing of this assembly. Many first-time deck builders (and some contractors) submit a plan that shows only the deck framing and labels the ledger as 'per code.' The city will issue an RFI: 'Provide a 1/2-inch scale section detail showing the ledger-to-house connection, flashing location, siding removal, and fastening schedule.' You'll need to redraw the detail, get it approved, and then the inspector will verify it during framing inspection (before you close up the siding). If you've done the flashing wrong—tape only, no metal flashing, or flashing installed backwards (water channeling into the house instead of away)—the inspector will make you tear it out and redo it. This delay costs time and money.
A practical note: some builders try to avoid the detail by using a bolted-on ledger with a neoprene seal or sealant. Midvale will not accept sealant as the primary WRB. Sealant fails in 3–5 years (UV, freeze-thaw cycling), and then you're back to water intrusion. The flashing+tape method is durable for 30+ years and is the only approved approach. Budget time in your plan review for this detail; don't assume it's obvious.
City of Midvale City Hall, Midvale, UT 84047
Phone: Search 'Midvale UT building permit' on the city website or call (801) 144-1110 (verify locally); typical main line is published on midvalecity.org | https://www.midvalecity.org (check for 'Permits' or 'Building Services' link; many Utah municipalities use e-Permit or InspectView portals)
Monday–Friday, 8:00 AM – 5:00 PM (verify locally; some cities close Wednesdays for lunch or have reduced hours)
Common questions
Can I skip the permit if my deck is under 200 square feet?
No. Midvale requires a permit for ALL attached decks, regardless of size. The attachment to the house (the ledger board) is what triggers the permit requirement, not the square footage. Freestanding ground-level decks under 200 sq ft and under 30 inches high may be exempt, but once you attach to the house, you need a permit. Many homeowners confuse the 200 sq ft rule (which applies to freestanding structures or decks built on grade) with the attachment rule. Attachment is the deciding factor in Midvale.
What happens during the footing pre-pour inspection?
The inspector will visit your job site and measure the depth of each post hole before you pour concrete. They'll verify that the hole is at least 48 inches deep (to account for frost depth in the Wasatch zone), that the diameter is adequate for the post size (typically 12 inches for a 6x6), and that the hole is below any visible expansive clay or organic material. If a hole is too shallow, the inspector will stop the pour and require you to dig deeper. This inspection takes 15–30 minutes per deck. You schedule it online or by phone after you've excavated but before concrete arrives. Plan 1–2 business days for turnaround.
Do I need an engineer stamp for my deck plan?
Not always. Simple decks up to about 200 sq ft with standard materials (pressure-treated posts, bolted ledger, standard joists) do not require an engineer stamp in Midvale. However, if your deck is large (over 300 sq ft), has an unusual shape, sits on clay soil with settlement concerns, or is near the Wasatch Fault and requires seismic bracing analysis, the city may ask for a Registered Professional Engineer (PE) stamp. If you're unsure, submit your plan first and ask the city in writing: 'Does this design require a PE seal?' Most simple decks don't.
How much does a Midvale deck permit cost?
Permit fees in Midvale run $200–$450, depending on the estimated construction cost (the city uses a valuation of roughly 1.5–2% of estimated cost, plus a $50–$100 base fee). A small deck (12×12, ~$10,000 estimated) costs about $200–$250. A large deck with composite decking and electrical (20×20, ~$25,000) costs about $350–$450. If you add an electrical permit for a GFCI outlet or lighting, add another $75–$150. If you hire an engineer for a stamped design, that's a separate cost ($500–$1,200).
Can I build the deck while my permit is being reviewed?
No. You must have a signed (approved) permit in hand before any work begins. Starting work without a permit is a violation and can result in a stop-work order, fines, and demands to remove the work or pay double permit fees. Plan 2–3 weeks for review before you order materials or start construction.
What is the ledger flashing requirement in Midvale?
IRC R507.9 requires a continuous moisture barrier (flashing) between the deck ledger and the house rim board to prevent water from entering the house. In Midvale, the standard detail shows self-adhering flashing tape (e.g., 3M 8067) applied to the house's sheathing, lapped under the house's weather barrier, plus a metal L-flashing installed on top of the tape. The ledger bolts pass through all layers. Siding is then replaced, covering the flashing. This assembly sheds water outward and down, preventing rot. If you skip or do this wrong, water will rot your house's frame in 3–5 years.
Do I need stairs on my deck, and does that require a separate permit?
Stairs are not required unless your deck is the primary egress route or if local fire code mandates them. If you do build stairs, they're covered under the same deck permit—no separate stair permit. However, stairs must comply with IRC R311.7: riser height 7.75 inches max, tread depth 10 inches min, and a landing at the top and bottom. If your deck height doesn't divide evenly by these dimensions, you may need to adjust the deck height or add a mid-landing. Include a detailed stair section on your permit plan.
Can I use my deck in winter or will the city shut it down?
Once your deck has passed all inspections and received a 'final' approval from the city, you can use it year-round. However, be aware that freeze-thaw cycles (especially in Midvale's 5B–6B climate) can cause seasonal movement and noise. Properly designed footings at the 48-inch frost depth will prevent heave, but the deck itself (ledger, bolts, posts) may shift slightly during freeze-thaw. This is normal and not a code violation. If you notice movement, have it inspected to ensure the ledger bolts haven't loosened.
What if my lot has a homeowners' association (HOA)?
HOA approval is separate from city permitting. The city will issue a permit if the design meets code; the HOA may have additional design restrictions (e.g., color, materials, height limits, setbacks). You should contact your HOA before designing the deck and get their approval in writing before submitting to the city. Some HOAs require architectural review that takes 2–4 weeks. Factor this into your timeline. The city does not enforce HOA rules, but the HOA can enforce them against you.
Can I pull the permit myself, or do I need a contractor?
Midvale allows owner-builders to pull permits for owner-occupied residential properties. You can submit the permit application, plan drawings, and fees yourself and attend inspections. However, you must be the owner and the work must be on your primary residence. If you're unsure about drawing or designing the deck, you can hire a deck contractor (who will pull the permit on your behalf) or an architect/engineer to create the plans. Many contractors charge $300–$800 to handle the entire permitting process, which can be worth the time savings and certainty of compliance.