Residential Building Inspector B1Wall Construction and Wall CoveringsEasy
A residential inspector is observing the installation of fiber cement lap siding. What is the minimum nominal thickness required for fiber cement lap siding?
- A1/4 inch
- B3/8 inch
- C5/16 inch
- D1/2 inch
Show answer & explanationAnswer & explanation
Correct answer: C. 5/16 inch
According to IRC R703.4.1, fiber cement lap siding shall have a minimum nominal thickness of 5/16 inch.
Why the other options are wrong
- A. 1/4 inch is too thin for fiber cement lap siding and would not meet the code requirements for durability and stiffness.
- B. 3/8 inch is thicker than the minimum required and often used for enhanced durability or specific aesthetic preferences.
- D. 1/2 inch is significantly thicker than the minimum and would be used in specialized applications, exceeding the code requirement.
Fiber Cement Siding Thickness
Fiber cement lap siding has a minimum required nominal thickness to ensure its structural integrity and weather resistance.
- Minimum 5/16 inch nominal thickness.
- Requires a water-resistive barrier behind it.
- Fastening requirements are specific to the material.
Memory trick: Fiber cement needs to be thick enough, like a strong shield for the house.