Your permit,
costed.

Almost always yes. Per IRC R105, permits are required for any structure attached to a dwelling (a ledger-attached deck) and most freestanding decks above 200 sqft or 30″ off grade. Skipping the permit risks: (1) failed inspections when you sell the home, (2) insurance non-coverage if someone is injured, (3) forced demolition orders, and (4) double-fee penalties when permits are pulled retroactively. Always pull the permit.

Per-sqft is a flat fee model: permit fee = area × $/sqft. Common in small towns + suburban jurisdictions with simple schedules. Pct-of-value scales with project value: permit fee = project value × pct%. Common in urban jurisdictions where a $40K composite deck gets charged more than a $15K PT deck. Many cities use "higher of both" — the calculator's default — which guarantees the city collects either way.

Three reasons: (1) urban building departments are larger and require more staff per project; (2) urban jurisdictions front-load plan-review work because deck designs vary more in dense areas (rooftop / cantilever / above garage); (3) urban impact fees + technology surcharges are typically higher. NYC is the extreme case at 1.45× the national baseline; Mississippi is the opposite at 0.70×. The 2× spread is real.

Per IRC R109, three mandatory: footing (after pour, before backfill), framing (after joists + beams + posts complete, before decking), and final (after everything — railing, stairs, electrical-if-applicable). Adding deck lighting requires an electrical rough-in inspection (+1). Adding a gas firepit or outdoor kitchen with gas plumbing requires a gas inspection (+1). Plan on 3-5 inspections total at ~$55-110 each depending on state.

Standard residential deck permit filing requires: (1) site plan showing deck footprint + property setbacks + utility easements, (2) framing plan with joist + beam + post sizes per DCA-6, (3) cross-section detail with ledger flashing + footing depth, (4) material list with species + dimensions, (5) sometimes property survey/plat. Stamped engineering is NOT required for standard residential decks under DCA-6 — only if your deck exceeds 200 sqft AND is more than 8 ft above grade in some jurisdictions.

Many states now charge a 0-5% technology surcharge on top of the base permit to fund digital permit-filing systems and online inspection scheduling. Pennsylvania charges 3% via UCC Construction Code Act, California charges up to 5% in some counties, Texas typically doesn't charge a state-level surcharge. The calculator applies your state's typical rate.

A flat per-project fee that funds local infrastructure (roads, schools, parks) impacted by new construction. For a deck addition, impact fees are typically $70-175 depending on state. Some jurisdictions waive impact fees for residential additions that don't expand living area — toggle includeImpactFee off if you've confirmed your locality waives it.

Limited room. Three approaches: (1) keep your deck under 200 sqft if it's near the trigger — many states have simpler permits below 200 sqft; (2) avoid electrical/gas additions in the initial permit (add deck lighting as a separate later project after final inspection) — saves the extra inspection; (3) submit complete documentation the first time — incomplete filings trigger plan-review re-fees which can double your permit cost. The biggest savings is doing the work correctly the first time.

Within ±15-25% for most residential projects in most states. The calculator uses state-average baselines + 2026-Q1 published fee schedules. Big cities (NYC, LA, SF, Chicago) within high-cost states often run 20-40% above the state average; rural counties run 20-40% below. For an exact quote, call your local building department's permit desk — most will give a quick estimate over the phone with just your project value + deck area.