Start-to-Start (SS) in Microsoft Project
What is Start-to-Start (SS)?
SS stands for Start-to-Start.
A Start-to-Start relationship means:
The successor task cannot start until the predecessor task has started.
In simple terms:
Task A starts → Task B can start.
The two tasks do not need to finish at the same time, but they are connected by their start dates.
Simple Diagram
Task A Start
↓
Task B Start
or
[Task A]
Start
↓
Start
[Task B]
Example
| Predecessor Task | Relationship | Successor Task |
|---|---|---|
| Electrical Installation | SS | Ceiling Work |
Explanation
When the electrical team starts installing conduits, cable trays, and wiring supports, the ceiling team can begin working in completed areas.
The ceiling work does not need to wait until all electrical installation is finished.
Electrical Installation
████████████████████
Ceiling Work
██████████████
Both tasks can progress at the same time.
Why Use SS?
Without SS:
Electrical Installation (Finish)
↓
Ceiling Work (Start)
The ceiling team must wait until all electrical work is completed.
With SS:
Electrical Installation (Start)
↓
Ceiling Work (Start)
Both teams can work simultaneously, reducing the project duration.
Construction Examples
MEP Works
| Task A | Relationship | Task B |
|---|---|---|
| Electrical Installation | SS | Ceiling Work |
Structural Works
| Task A | Relationship | Task B |
|---|---|---|
| Rebar Installation | SS | Quality Inspection |
Interior Works
| Task A | Relationship | Task B |
|---|---|---|
| Tile Installation | SS | Material Quality Check |
Site Management
| Task A | Relationship | Task B |
|---|---|---|
| Construction Work | SS | Progress Monitoring |
Real Construction Example
Office Building Project
Suppose:
| Task | Duration |
|---|---|
| Electrical Installation | 10 Days |
| Ceiling Work | 8 Days |
If Ceiling Work uses FS, it starts after Day 10.
Total duration:
Electrical Installation: Day 1–10
Ceiling Work: Day 11–18
Total = 18 Days
If Ceiling Work uses SS, it starts when Electrical Installation starts.
Electrical Installation: Day 1–10
Ceiling Work: Day 1–8
Total = 10 Days
The schedule becomes much shorter.
Benefits of SS Relationships
✅ Allows parallel work.
✅ Reduces project duration.
✅ Improves team productivity.
✅ Makes schedules more realistic.
✅ Helps fast-track construction projects.
Comparison of Task Relationships
| Type | Full Word | Meaning |
|---|---|---|
| FS | Finish-to-Start | Task B starts after Task A finishes |
| SS | Start-to-Start | Task B starts after Task A starts |
| FF | Finish-to-Finish | Task B finishes after Task A finishes |
| SF | Start-to-Finish | Task B finishes after Task A starts |
Easy Way to Remember
SS = Start Together
Think:
"Once the first task starts, the second task is allowed to start."
Example
Electrical Installation
Start
↓
Ceiling Work
Start
The tasks may finish on different days, but they begin together.
Key Lesson
Start-to-Start (SS) means:
The successor task cannot start until the predecessor task has started.
This relationship is commonly used in construction projects when two activities can be performed in parallel, helping teams save time and shorten the overall project schedule.