Start-to-Finish (SF) in Microsoft Project
What is Start-to-Finish (SF)?
SF stands for Start-to-Finish.
This is the least common and most difficult task relationship to understand in Microsoft Project.
A Start-to-Finish relationship means:
The successor task cannot finish until the predecessor task has started.
In simple terms:
Task B cannot finish until Task A starts.
Simple Diagram
Task A Start
↓
Task B Finish
or
[Task A]
Start
↓
Finish
[Task B]
Why is SF Rarely Used?
Most projects naturally follow:
Finish-to-Start (FS)
Start-to-Start (SS)
Finish-to-Finish (FF)
The SF relationship is unusual because it links:
The start of one task
To the finish of another task
This type of dependency is mainly used for shift changes, handover operations, and continuous services.
Classic Example
Security Guard Shift
| Predecessor Task | Relationship | Successor Task |
|---|---|---|
| Day Shift Starts | SF | Night Shift Ends |
Explanation
The night shift guard cannot leave until the day shift guard arrives and starts work.
Night Shift
████████████ Finish
↑
│
Day Shift
Start ████████████
The night shift finishes only after the day shift starts.
Construction Example
Site Supervision Handover
| Predecessor Task | Relationship | Successor Task |
|---|---|---|
| New Supervisor Starts | SF | Existing Supervisor Ends |
Explanation
The current supervisor remains responsible until the replacement supervisor starts work.
This ensures continuous site management without gaps.
Facility Management Example
| Predecessor Task | Relationship | Successor Task |
|---|---|---|
| New Generator Starts | SF | Old Generator Shutdown |
Explanation
The old generator cannot be shut down until the new generator starts operating.
This prevents power interruption.
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 Applications of SF
Although uncommon, SF can be useful for:
Workforce Handover
New Shift Starts → SF → Old Shift Ends
Site Management
New Supervisor Starts → SF → Previous Supervisor Ends
Equipment Replacement
New Generator Starts → SF → Old Generator Stops
Temporary Facilities
New Water Supply Starts → SF → Temporary Water Supply Ends
Easy Way to Remember
SF = Start Before Finish
Think:
"The new task must start before the old task can finish."
Example
New Supervisor Starts
↓
Old Supervisor Ends
or
New Shift Starts
↓
Old Shift Ends
Key Lesson
Start-to-Finish (SF) means:
The successor task cannot finish until the predecessor task has started.
It is the least-used dependency type in Microsoft Project and is mainly applied to handovers, shift changes, equipment replacement, and situations where one operation must continue until another operation has officially begun.
Quick Memory Trick
FS = Finish First, Start Next
SS = Start Together
FF = Finish Together
SF = Start Before Finish
Among these four relationships, FS (Finish-to-Start) is by far the most commonly used in construction scheduling.