What happens if you skip the permit (and Johnston requires one)
- Stop-work order and $500–$1,000 fine from the Johnston Building Department; you'll then pay double permit fees when you re-pull, plus re-inspection delays that can add 3–4 weeks.
- Home-sale disclosure: any unpermitted deck must be reported on the Iowa Real Estate Transfer Disclosure Statement (TDS), which kills buyer confidence and triggers lender appraisal holdups — expect 10–20% price hit or outright withdrawal.
- Insurance denial: if a deck collapses (ledger pulls away, rotten band board, frost heave on shallow footings), your homeowner's policy will deny the claim and investigate who permitted it; you're liable for injuries.
- Neighbor complaint: decks visible from the street or adjacent properties invite complaints; Johnston code enforcement responds to documented violations and will issue a notice-of-violation requiring removal or retroactive permitting at 2–3x the original cost.
Johnston attached deck permits — the key details
Timeline and process: submit your permit application (online portal preferred) with site plan, elevation drawing, framing plan, and footing detail. The city typically acknowledges receipt within 1–2 business days and assigns a plan reviewer. Review takes 5–7 business days; the reviewer may issue a request-for-information (RFI) if anything is missing (common: unclear footing depth, missing ledger flashing detail, or unlabeled joist spacing). You have 14 days to respond to an RFI; if you ignore it, the application dies and you re-submit. Once the plan is approved, you get a permit card (digital or paper) and can start work. Call for footing pre-pour inspection at least 24 hours in advance; the inspector verifies hole depth and location. After the pre-pour, you pour concrete and set posts. Call for framing inspection once the deck frame (ledger, beams, joists, stairs) is in place but before you attach railings or decking boards. The framing inspector checks ledger flashing, post-to-beam connections, joist hangers, beam straightness, and railing height; this is the critical inspection and often takes 30–60 minutes. Defects must be corrected and re-inspected (additional fee, usually $75). Once framing passes, you can install decking (boards), railings, and stairs. Call for final inspection after everything is complete; the inspector walks the deck, checks handrails and balusters, verifies stair dimensions, and signs off. Typical timeline from permit submission to final inspection: 3–4 weeks if everything goes right; 6–8 weeks if there are RFI delays or framing defects. Don't start footings until you have a permit card; do-it-anyway work is a violation and will trigger a stop-work order.
Three Johnston deck (attached to house) scenarios
Frost depth and footing failure: why Johnston's 42-inch requirement matters
Concrete quality matters too. Pour frost-protected footings with concrete rated at least 3,000 psi (standard ready-mix concrete); avoid weak mixes or recycled concrete. The footings must be poured in one continuous pour per hole (no layering or patching). Above-grade concrete pads (the part that sticks out of the ground) must be at least 4 inches above finished grade and level; if the pad is flush with grade or below, water will pool and cause the post to rot. Many Johnston decks fail because the contractor prioritized speed and buried the concrete pad 1–2 inches below grade, creating a moisture trap.
Ledger flashing and water management: the #1 Johnston deck citation
Ledger-to-rim-board fastening is equally critical. Through-bolts (½-inch diameter bolts passing through the rim board and ledger, secured with washers and lock washers) must be spaced no more than 16 inches on center; this spacing carries the full lateral load of the deck (wind, snow, seismic forces in some jurisdictions) plus the dead load of the deck frame. Under-spaced bolts (24 or 32 inches apart) will allow the ledger to twist or separate under load. The inspector will measure bolt spacing during framing inspection; if spacing is wide, they'll require additional bolts to be drilled and installed. Some contractors prefer lag screws or nails, which are code-compliant (IRC R507.9.2 allows lag screws, ½ inch diameter, 8 inches on center, but through-bolts are the industry standard and the inspector's preference because they're more reliable in tension).
Johnston City Hall, 6320 Merle Hay Road, Johnston, IA 50131
Phone: (515) 278-0971 (main number; ask for Building or Planning Department) | https://www.johnstoniowa.com (check 'Services' or 'Building Permits' for online permit portal or contact information)
Monday–Friday, 8:00 AM – 5:00 PM (verify by calling or visiting the city website)
Common questions
Can I build an attached deck without a permit if it's low and small?
No. Johnston requires a permit for any attached deck, regardless of size or height. This is because attached decks create a structural connection to the house (the ledger board), and that connection must be inspected to prevent failure and injury. Freestanding decks under 30 inches high and under 200 square feet may be exempt in some jurisdictions, but an attached deck is never exempt. Pulling a permit costs $200–$400 and takes 2–3 weeks; skipping it costs $500–$1,000 in fines, plus double permit fees and disclosure hits when you sell.
Do I need a contractor's license to build a deck in Johnston?
No, if you're the owner-builder (you own the house and are building it for yourself, not for sale). Iowa allows owner-builders to pull permits and do the work themselves. If you hire a contractor, they must be licensed (Iowa Contractor's Board); if the deck is under a certain threshold (typically $5,000 in labor), some contractors claim exemptions, but Johnston will verify licenses at the building phase. The safest approach: hire a licensed deck contractor. If you're building it yourself, you'll pull the permit and be responsible for passing all inspections.
What's the most common reason Johnston inspectors fail a deck framing inspection?
Ledger flashing. The inspector is looking for galvanized or aluminum flashing bent into an L, slipped under the house rim sheathing, with weep holes drilled every 16 inches. Missing flashing, incomplete installation, or flashing buried under house trim is the #1 failure. The second most common failure is unequal stair riser heights or unstable stair stringers. Get the flashing detail right before framing inspection, and you'll pass.
Can I use a freestanding deck attached to the house with bolts instead of a ledger board?
No. A structure bolted to the house is still an attached deck and triggers the same permit and structural requirements. The only way to avoid the ledger-board requirement is to build a true freestanding deck (no connection to the house), which must still have deep footings and comply with IRC R507 for guard rails and stair dimensions, but doesn't require ledger inspection. If you're bolting anything to the house, you need a ledger and flashing.
How deep do footing holes need to be in Johnston?
42 inches below finished grade, minimum. This is Johnston's frost-depth requirement. Holes must be dug to at least 42 inches; if soil conditions are difficult (clay, rock), you may need to pour concrete deeper or use a frost-protected shallow foundation (FPSF) with insulation (not common in residential decks, but ask the inspector if you encounter difficult soil). The inspector will measure hole depth at pre-pour inspection with a tape measure; no shortcuts.
Do Johnston deck stairs need a handrail if the deck is low?
Yes, if the stair has four or more risers. IRC R311.7 requires a handrail (34–38 inches above stair nosing) on any flight of four or more steps. If your deck is 18 inches above grade, that's about 2–3 steps, so no handrail required. If your deck is 30 inches above grade, that's about 4–5 steps, so handrail is required. The inspector will verify stair count and handrail height during framing inspection. Balusters (vertical spindles) must be spaced no more than 4 inches apart (4-inch sphere test) to prevent child entrapment.
What happens if I pour footing concrete before the inspector clears the pre-pour inspection?
You're violating the permit condition. If the inspector arrives and sees an unchecked hole filled with concrete, they'll note it as a violation, issue a stop-work order, and may require you to jackhammer out the concrete to verify the depth. This is expensive and delays the project 1–2 weeks. Always call for inspection before pouring; the city will respond within 1–2 business days.
Can I add a hot tub to my deck without a separate permit?
No. A hot tub is a plumbing fixture and electrical load; it requires a separate plumbing permit, electrical permit, and structural review to ensure the deck can support the weight (hot tub + water can exceed 3,000 lbs). You'll need a licensed plumber and electrician. The city will require a plumbing inspection (drain, vent, material certification) and electrical inspection (circuit, GFCI, breaker). Plan for an additional 3–4 weeks and $2,000–$4,000 in plumbing and electrical costs. Size the deck framing (beams, joists) for the extra load before you submit the building permit; include a note on the framing plan if you're planning a future hot tub.
Do I need soil testing or a geotechnical report to build a deck in Johnston?
Not for a standard residential deck. Johnston does not require soil testing for deck footings; the 42-inch frost depth is the only mandate. If your lot has unusual soil conditions (expansive clay, high water table, fill material), the inspector may ask for a footing detail or site evaluation, but this is rare. If you hit rock or water at 30 inches, document it and call the inspector for guidance; they may allow a footing pad set higher with expanded concrete or may require deeper digging elsewhere. Most Johnston lots have loess or glacial till that's straightforward to dig.
How long does a Johnston building permit stay valid?
Typically, 180 days (6 months) from the date of issuance. If you haven't started work within 180 days, the permit expires and you must re-apply and pay again. If work is active (you've had at least one inspection within the validity period), the permit remains active as long as you're making progress. Once you start, don't go dormant for more than 6 months; if you pause mid-project and lose your permit, re-pulling costs another $200–$400. Verify the exact expiration date on your permit card; the city's website or a phone call can confirm.