Start-to-Start (SS)

A Start-to-Start relationship links the initiation of two tasks, meaning the successor activity cannot start until the predecessor activity has started. This type of relationship allows tasks to progress in parallel rather than strictly sequentially, making it ideal for work that can overlap without waiting for full completion of prior tasks. 

Using SS relationships effectively can help shorten project timelines, improve resource utilization, and maintain logical workflow when tasks are interdependent but don’t need to wait for full completion.

Example: Painting interior walls (successor) can begin once drywall installation (predecessor) has started, even though the drywall may not be fully finished. This allows crews to work concurrently, reducing idle time while still maintaining proper sequencing.