How far should decks constructed of treated wood be above grade according to the IRC?

According to the International Residential Code (IRC), decks constructed of treated wood must be constructed with a minimum clearance of 6 inches above grade. This requirement is significant for several reasons.

Primarily, maintaining a clearance of 6 inches helps ensure proper ventilation and drainage around the deck structure. It reduces the likelihood of moisture accumulation, which can lead to wood rot, pest infestation, and degradation of the treated wood over time. Adequate clearance also minimizes direct contact with the soil, which can be a source of additional moisture and harmful insects.

Furthermore, the 6-inch requirement aligns with general building practices aimed at promoting durability and safety in construction. It is an essential consideration for the long-term performance of the deck, helping homeowners avoid costly repairs and safety issues related to structural integrity.

Other options suggest greater or lesser clearances, which do not comply with the IRC standards and may compromise the deck's longevity and reliability. By adhering to the specified minimum of 6 inches, builders and homeowners can ensure that the deck is both compliant and structurally sound.