Buried Utility or Rock Encountered During Post Dig: Response
Purpose
A utility strike ends with a release from the utility owner. A rock refusal ends with a hole that still needs to hit a depth nobody can shortcut. Both leave a crew standing over a hole that isn't going in the ground the way the plan said it would, and what the crew does next decides whether this is a five-inch relocation nobody notices or a footing that fails two years from now because someone set a post at partial depth and backfilled over it rather than stop and ask. This standard is the decision the crew makes once the strike is released or the refusal is confirmed: relocate, reduce depth by an approved method, or escalate, with the record that protects the shop when a customer or an inspector asks why a post sits somewhere other than the plan.
Scope
Covers what happens to the job once a utility find has been released by the utility owner, or a rock refusal has been confirmed at a specific post location, through a documented resolution and a completed plumb-and-line check on the resulting hole. It does not cover the moment-of-strike stop-and-response, clearing the area, calling the utility owner, holding for release; Fence Line Utility Locate and Hand Dig Standard owns that step and this standard assumes it has already happened. It does not cover the state-specific notice window, tolerance-zone distance, or penalty structure for a utility strike; Call Before You Dig State 811 Trigger owns that. It does not cover the setting procedure itself once a hole is ready; Fence Post Setting Depth and Concrete and Helical Pier Post Installation Technique own that.
Roles and responsibilities
| Role | Owns | Hands off |
|---|---|---|
| Technician | Measures refusal depth, probes for obstruction edges, executes the approved relocation or depth-reduction method, logs the result | A resolved hole with a documented method before setting begins |
| Crew lead | Approves relocation distance and layout impact, authorizes rental equipment or a core-drill subcontractor, triggers a change order when scope changes | A signed-off resolution before the crew moves past that post |
| Shop | Issues the change order to the customer, updates the permit or plan if spacing or post count changes, files the record | A documentation trail that explains any post whose location or depth differs from the original plan |
Procedure
Confirm the location is actually clear to dig before treating it as resolved: for a utility find, confirm the utility owner's documented release is on file per the hand-dig standard's log; for a suspected rock refusal, measure the depth actually reached with a tape against the minimum this post requires (a third of total post length, 2 feet, or the local frost line, whichever is deepest, per Fence Post Setting Depth and Concrete). Acceptance: a logged release reference, or a measured depth compared in writing against the required minimum. Wrong looks like calling a slow-digging hole "rock" because the auger is bogging down, without ever getting a tape on it, when a few more minutes of hand work would have cleared a root ball or an old footing chunk. Stop rule: no measured depth or release reference on file means no refusal or resolution decision gets made yet. Hazard: none new at this step; the strike hazard itself is already controlled by the release requirement in the sibling standard.
At a confirmed rock refusal, probe a foot in every direction from the hole center with a digging bar to find whether the obstruction has edges (an isolated boulder or slab) or continues with no edge found (a ledge or shelf). Acceptance: probe result logged as either "edge found within 12 inches" with the direction noted, or "no edge found within 12 inches in any direction checked." Wrong looks like declaring the whole run "rock" after probing the one hole that stopped the auger, when a ledge commonly dips or ends within a couple of feet and the crew standing over the problem on a hot afternoon is the least motivated to keep probing. Stop rule: fewer than three probe directions checked means no classification gets logged. Hazard: a bar under load can skip off a sloped rock face without warning; keep the free hand and both knees out of the bar's travel path rather than braced against the handle for leverage.
For an isolated obstruction, relocate within tolerance: shift the post up to 6 inches off the string line in either direction, provided the resulting spacing to both neighboring posts still passes Post Plumb and Line Verification Standard's line check; a shift beyond 6 inches, or any shift that changes a panel count or a gate opening width, stops here for crew-lead sign-off and a customer change order before digging resumes. Acceptance: relocation distance measured with a tape and logged at the post, sign-off obtained if over 6 inches or touching panel or gate layout. Wrong looks like nudging a post a little at each of several holes along one run to dodge small pockets of rock, with nobody adding up the drift until the last panel or the gate opening comes up short measured against the whole run. Stop rule: every relocation gets measured and logged at the time it happens, not reconstructed later from memory. Hazard: none new, this is a layout decision.
For a continuous ledge, or a find that can't be relocated within tolerance, choose one documented method rather than setting at whatever depth the obstruction allowed: core-drill to full required depth, a surface-mounted post base rated for this post's height and the site's wind exposure per its manufacturer chart, or an engineer's sign-off on a shallower footing with a wider base. If the hole can't be finished that day, cover it and mark it with a cone or barricade before the crew leaves, and note the covered, unset hole on the job record so it isn't mistaken for backfilled ground overnight. Acceptance: one method selected with its basis recorded (equipment scheduled, base rating checked against the manufacturer's chart, or engineering sign-off on file); an overnight hole is covered, marked, and closed out with a set post before the job record shows it complete. Wrong looks like backfilling over a post at whatever depth the rock allowed and planning to mention the shortfall later, which leaves a footing nobody can find and no record explaining why it's shallow. Stop rule: no post gets backfilled below its required minimum depth without one of the three approved methods on file at the time of setting. Hazard: core-drilling and mechanical breaking both throw rock chips; eye protection is required for everyone within the chip radius, and a dust mask for anyone running extended breaking on dry rock, not only the operator. An unset hole left overnight is also its own fall-in and trip hazard for a child, a pet, or the homeowner walking the yard after dark, which is what the cone or barricade in this step controls; it goes up before the crew leaves, not the next morning before starting back up.
Where a rented rock auger, breaker, or a subcontracted core-drill rig is brought onto the job, confirm the operator has the manufacturer's guard installed before first use that day, hold every other crew member outside the tool's posted swing or kickback radius, and confirm the drive head is fully stopped and locked out before anyone clears packed spoil from the bit or flighting by hand. Acceptance: guard verified in place, radius held clear during every run, tool confirmed stopped before hand-clearing begins. Wrong looks like a second crew member reaching in to clear the flighting while the operator holds the trigger at idle, on the assumption idle means safe, when a loaded auger can catch and spin without warning the moment tension releases. Stop rule: any hand goes near the bit or flighting while the drive head still has power, the job stops until the tool is fully de-energized, not just released. Hazard: a rock auger or breaker can kick back hard off a seamed or sloped face; the operator keeps a firm two-hand grip and a stable stance, and anyone not operating stays outside the posted radius for the whole cycle, not just the first cut.
Once the hole reaches an approved depth by one of the methods in step 4, run the full plumb-and-line check from Post Plumb and Line Verification Standard before setting, since a relocated or core-drilled hole is exactly the off-string, off-plan location that check exists to catch. Acceptance: a completed plumb-and-line log entry for this post before concrete, base, or pier goes in. Wrong looks like treating the rock problem as solved the moment the hole is deep enough and skipping the plumb-and-line pass because this post already got extra attention today. Stop rule: no post gets set without a completed plumb-and-line entry, refusal delay or not. Hazard: none new, covered by the referenced standard.
Log the finding for each affected post before the crew leaves that section of the run: what was encountered (utility type and release reference, or rock classification), the method chosen, any relocation distance, and whether a change order was issued. Acceptance: entry complete and tied to the specific post number, in the same log the utility-locate standard uses. Wrong looks like one line at the bottom of the day's paperwork noting "hit rock a few times, worked around it," which leaves nothing for the shop to point to if a customer later asks why one post's spacing reads differently from its neighbors. Stop rule: a section with an unresolved refusal, an undocumented relocation, or an uncovered open hole does not get marked complete on the job record.
The record this produces
The log ties each affected post to what was found, the method used to resolve it, and any resulting change to layout or scope. A change order tied to a specific post number and a documented reason is defensible when a customer questions an added line item weeks later; a change order that just says "rock" is not. The same log is what a crew lead reviews across a season to see whether one soil type or neighborhood generates enough rock refusals to justify pricing a core-drill day into every estimate there up front.
Worked pass, with a step that failed
A ten-post backyard privacy run. Post 6 stops the auger. Step 1: depth check reads 14 inches, short of the 24-inch minimum this post height and frost line require, logged as a suspected refusal, not slow digging. Step 2: probing finds a clean edge 8 inches to the north. Step 3: relocated 5 inches, inside the 6-inch tolerance, no change order needed, and spacing to posts 5 and 7 still passes the line check.
Post 7, right next to it, also stops the auger. Step 2: probing in all directions finds no edge within 12 inches, a continuous ledge. Step 3 doesn't apply, there's no isolated edge to relocate around. Step 4: the crew's first instinct is to set post 7 at the 14 inches the rock allows and add extra concrete to compensate, which the stop rule blocks outright, since that's neither the required depth nor one of the three approved methods. A surface-mounted base is considered next, but its manufacturer chart caps it below this post's height at this site's wind exposure, so it's rejected and logged as rejected, not just skipped. Core-drilling is selected instead; the subcontractor can't get there until the next morning. The open hole gets covered with plywood and marked with a cone before the crew leaves, logged as an open, unset hole rather than left to look like undisturbed ground.
Step 5: the core-drill operator arrives, guard confirmed on, crew held clear of the posted radius through the run. Step 6: once the drilled hole reaches the required depth, the plumb-and-line check runs and passes. Step 7: both posts logged, post 6 with its relocation distance and no change order, post 7 with the rejected base method, the core-drill method used, and a change order issued for the return trip.
References
- See related: Fence Line Utility Locate and Hand Dig Standard, for the moment-of-strike stop-and-response and release documentation this standard assumes has already happened.
- See related: Call Before You Dig State 811 Trigger, for the state-specific notice window and tolerance-zone distance.
- See related: Post Plumb and Line Verification Standard, for the plumb and line check every relocated or depth-adjusted hole runs before setting.
- See related: Fence Post Setting Depth and Concrete, for the depth-rule figures this standard's refusal check compares against.
- Common Ground Alliance Best Practices, the damage-prevention standard most state statutes adopt by reference.