Commercial Building Inspector B2Building EnclosureMedium
A commercial building inspector is reviewing the design for a new five-story office building in a high-wind area. The plans indicate that the exterior walls will be clad with masonry veneer. What is the minimum air space required between the masonry veneer and the sheathing for this construction?
- A2 inches (50.8 mm)
- B1 inch (25.4 mm)
- C4 inches (101.6 mm)
- D1/2 inch (12.7 mm)
Show answer & explanationAnswer & explanation
Correct answer: B. 1 inch (25.4 mm)
IBC Section 1405.10.4 specifies a minimum 1-inch air space between the masonry veneer and the sheathing for exterior walls to allow for drainage and ventilation, particularly important in high-wind areas.
Why the other options are wrong
- A. While beneficial, a 2-inch air space is not the minimum required by the IBC for this application.
- C. A 4-inch air space is excessive and not the minimum requirement for masonry veneer construction.
- D. This air space is typically too small for effective drainage and ventilation behind masonry veneer.
Masonry Veneer Air Space
The clear space between the back of masonry veneer and the sheathing or structural wall, essential for drainage and ventilation.
- Minimum 1 inch required by IBC for exterior walls.
- Prevents moisture accumulation behind the veneer.
- Allows for drying of the wall assembly.
Memory trick: Masonry needs room to breathe, a one-inch gap lets moisture leave.