Concerning exterior sheathing, how far above grade should it extend?

Concerning exterior sheathing, how far above grade should it extend?

• A. 8 inches
• B. 10 inches
• C. 6 inches
• D. 4 inches

Answer: (C)

The main idea is protecting the wood and sheathing from moisture and pests at the base of the wall. Keeping exterior sheathing a safe distance above grade helps prevent splash moisture from the ground from soaking into the wood, reduces the risk of rot, and creates a buffer against termites or other intrusion. The standard minimum you’ll often see in building codes is six inches above finished grade, measured from the top of the grade. That’s why six inches is the best choice here. Four inches is too close to the ground and increases moisture risk. Eight or ten inches exceed the typical minimum in most codes, though some places or conditions might require more; six inches is the commonly adopted baseline.

The main idea is protecting the wood and sheathing from moisture and pests at the base of the wall. Keeping exterior sheathing a safe distance above grade helps prevent splash moisture from the ground from soaking into the wood, reduces the risk of rot, and creates a buffer against termites or other intrusion. The standard minimum you’ll often see in building codes is six inches above finished grade, measured from the top of the grade. That’s why six inches is the best choice here.

Four inches is too close to the ground and increases moisture risk. Eight or ten inches exceed the typical minimum in most codes, though some places or conditions might require more; six inches is the commonly adopted baseline.