Deck footings must bear below the local frost depth to prevent frost heave: 30 inches minimum in the Salt Lake City valley floor; 36 inches in foothill communities (Sandy, Draper, Cottonwood Heights); 36–42 inches in Wasatch Back communities (Park City, Heber City); and 42–48 inches in mountain communities above 6,000 feet. Shallow footings are the most common structural failure on Utah decks — a deck with 18-inch footings will be visibly out of level within 5–10 years and structurally compromised within 15 years as frost heave lifts and tilts the footing with every winter cycle. The marginal cost to excavate to proper depth during construction is modest; the cost to replace shallow footings after the deck is built is enormous. RainFire Builders installs all deck footings to the local frost depth minimum, confirmed by the building department inspection before concrete is placed.