Rabbeted siding minimum lap is 1/2 inch. Which option shows this value?

Rabbeted siding minimum lap is 1/2 inch. Which option shows this value?

• A. 1/4 inch
• B. 1/2 inch
• C. 3/4 inch
• D. 1 inch

Answer: (B)

Rabbeted siding relies on an overlap between courses to shed water, and that overlap must be at least half an inch to provide a weather-tight seal and to accommodate wood movement from moisture and temperature changes. The value that matches this minimum is 1/2 inch. A smaller lap, like 1/4 inch, would leave gaps that can let water in, while larger overlaps such as 3/4 inch or 1 inch exceed the minimum and are not required when only the minimum is asked.