What is the minimum dimension you should extend siding below the sill plate?

The minimum dimension that siding should extend below the sill plate is 1 inch. This practice is important for preventing water infiltration into the building's structure. Water can accumulate around the base of the building, and if siding is not properly extended below the sill plate, it can lead to moisture problems, including wood rot and mold growth.

A 1-inch extension offers a sufficient barrier to redirect water away from the bottom of the wall framing and protect the sill plate. This is a common building practice aimed at ensuring durability and longevity of the home, as it helps in managing the moisture that can come from rain or snowmelt.

While some professionals may prefer greater extensions for added protection, the minimum requirement established in building codes and best practices is 1 inch. This keeps the design efficient while still addressing moisture management effectively.