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 starts.
In simple terms:
Two tasks are linked by their start dates.
The tasks do not need to finish together, but they must start together (or the successor starts after the predecessor starts).
Simple Example
| Predecessor Task | Relationship | Successor Task |
|---|---|---|
| Electrical Installation | SS | Ceiling Work |
Explanation
When Electrical Installation starts, Ceiling Work can start.
For example:
| Task | Start Date |
|---|---|
| Electrical Installation | Monday |
| Ceiling Work | Monday |
The ceiling team can begin work after the electrical team has started installing conduits, cables, or supports.
Both activities can proceed at the same time.
Construction Example
Plumbing and Wall Construction
| Predecessor Task | Relationship | Successor Task |
|---|---|---|
| Plumbing Installation | SS | Wall Construction |
Explanation
Once plumbing installation begins, wall construction can also begin in areas where plumbing rough-ins have already been completed.
Both teams work simultaneously.
Real Site Example
Reinforcement and Formwork Inspection
| Predecessor Task | Relationship | Successor Task |
|---|---|---|
| Rebar Installation | SS | Quality Inspection |
Explanation
The inspection team can start inspecting completed sections as soon as rebar installation starts, without waiting for the entire installation to finish.
When Should You Use SS?
Use Start-to-Start when:
Multiple teams can work simultaneously.
One task only needs another task to begin before it can start.
You want to shorten the project schedule.
Activities overlap naturally.
Benefits of SS Relationships
✅ Reduces project duration.
✅ Allows parallel work.
✅ Improves resource utilization.
✅ Speeds up project completion.
✅ Creates a more realistic construction schedule.
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 |
Construction Examples of SS
Structure Works
Column Casting → SS → Beam Reinforcement
MEP Works
Electrical Installation → SS → Ceiling Work
Interior Works
Tile Installation → SS → Grouting Preparation
Site Management
Construction Work → SS → Progress Monitoring
Procurement
Material Delivery → SS → Material Inspection
Easy Way to Remember
SS = Start Together
Think:
"Once the first task starts, the second task is allowed to start."
Example
Electrical Installation → SS → Ceiling Work
Plumbing Installation → SS → Wall Construction
Rebar Installation → SS → Inspection
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 proceed in parallel, helping teams work more efficiently and reducing overall project duration.