At which level does sill installation typically begin?

Sill installation typically begins at the bottom of the door opening. The sill serves as the foundational component that helps support the door frame and ensures proper alignment of the doors during installation. Starting at the bottom allows for proper leveling and stability, as the sill needs to be accurately placed to prevent issues with door operation and to maintain the integrity of the door system.

In elevator door installations, the sill is critical for providing guidance and support for the doors, as well as effectively sealing the entrance to minimize air infiltration. Installing from the bottom helps in achieving a consistent height and alignment for the rest of the installation process, which includes mounting the door frames and operating mechanisms above it. This method also aligns with best practices in construction, where starting from a fixed reference point (like the bottom sill) helps in ensuring that all other components are installed correctly in relation to that point.