Offset stakes are set at a fixed distance from the construction centerline so that when construction disturbs the centerline stakes, the offset stakes remain intact and can be used to re-establish the centerline. Common offsets: 15–25 ft from road centerline; 5–10 ft from the edge of a utility trench. Always record the offset distance on each stake lath so any crew member can re-establish the line.
Why Offset Stakes?
Construction activity — excavation, grading, equipment traffic — destroys grade stakes and alignment stakes. If the alignment is staked directly on the construction line, you lose it the moment work begins. Offset stakes set at a safe distance from the construction activity allow the alignment and grade to be re-established from surviving stakes at any point during construction.
Standard Offset Distances
| Application | Typical Offset |
|---|---|
| Road centerline | 15–25 ft from CL |
| Curb and gutter | 5–10 ft from face of curb |
| Utility trench | 5–8 ft from trench centerline |
| Building foundation | 3–5 ft from wall line |
| Batter boards (foundation layout) | 4–6 ft from corner |
The offset distance must be: (1) far enough from the construction edge to survive construction activity, and (2) close enough that the alignment can be practically re-established from the stakes. For road work, the offset is typically just outside the limits of construction.
Setting Offset Stakes
- Stake the construction line (centerline, edge of pavement, pipe centerline) first.
- From each on-line stake, measure the offset distance perpendicular to the alignment and drive the offset stake.
- Record on the lath: the station, the offset distance and direction (e.g., “25 RT”), and any cut or fill information.
- Protect offset stakes from equipment. In active areas, use guard stakes or flag them conspicuously.
Recovering the Alignment from Offset Stakes
When the original alignment stakes are destroyed, re-establish them from the offset stakes:
- Use a tape or total station to re-stake the construction line at the recorded offset distance from the surviving offset stakes.
- Verify the recovered alignment by checking at least two stations with a total station or by taping distances between stakes.
- If multiple offset stakes are missing, you may need to re-stake from control points — do not recover alignment from a single offset stake without a check.
See also: Staking Out Building Corners and Slope Staking on Road Construction Projects.