Fence Line Layout and String Line Standard

Purpose

A fence built on a layout nobody verified goes in wrong once and stays wrong for its life. A line struck from an old photo or "where the last fence stood" routinely sits eight inches to two feet off the deeded property line, an encroachment the neighbor eventually surveys and disputes, or a strip of the customer's own yard given away on the far side of the line. A string line that sags over a long run, or gets measured post to post instead of from a fixed reference, compounds a small error into a post pattern where the panels won't fit and the last bay comes up short by inches nobody can absorb. This procedure exists so the line, the corners, and every post station are confirmed and marked before a single hole is dug, not discovered wrong after concrete has cured around the first ten posts.

Scope

Covers confirming the property line, the utility locate, permanent corner references, stringing and tensioning the line, marking post stations, and the pre-dig walk. Applies ahead of any fence material install on this shelf: wood, vinyl, chain link, ornamental, or wire.

Does not cover clearing trees or obstructions from the confirmed line; the fence-line tree removal preparation SOP owns that. Does not cover post-hole depth, diameter, or concrete technique once a station is marked; the post setting depth and concrete HowTo owns that. Does not cover resolving a line dispute or the permit process; the shared fence neighbor dispute protocol and the residential vs commercial fence permit process SOPs own those. Does not cover picket, panel, or wire spacing math within a confirmed span; each material's own installation HowTo owns that layer, working from the stations this procedure hands off.

Roles and responsibilities

Procedure

1. Confirm the property line from a survey, a found and verified corner pin, or a written agreement between adjacent owners, never from where an old fence used to stand. Pull the plat or prior survey from the office file; where none exists, locate the platted corner with a metal detector and verify it two ways, triangulating from two other known plat points rather than a single distance-and-bearing shot from one reference. Acceptance: a confirmed corner at both ends of the run, source recorded, on file before layout continues. Wrong looks like squaring the new line off the remains of the old fence, commonly built a foot or more off the actual line by an installer who made the same shortcut before you. Stop rule: no confirmed corner from a survey, a verified pin, or a signed agreement, no marking and no digging; escalate to a licensed surveyor or the permit process SOP. Hazard: none, desk and hand-tool verification only.

2. Pull the utility locate before any stake goes into the ground with a driven point, and confirm the ticket is still current when digging starts. Call 811 or the state one-call center the required lead time ahead, typically two full business days minimum, and treat marks as expired past 15 working days from the call, a conservative default; confirm your state's actual window and use whichever is shorter. Acceptance: a logged ticket number, all flags and paint present, marks dated within the current window. Wrong looks like reusing a ticket or paint left over from an earlier job on the same street. Stop rule: no current ticket, no driven stakes or probing past the tolerance zone, no digging. Hazard: hand-driving a stake or probe into an unmarked area can strike a shallow line, since irrigation, low-voltage lighting, or a service drop often run shallower than a locate crew flags for a fence job; set stakes by hand pressure only within the tolerance zone until the ticket confirms clear, and if a line is struck, cut, or you smell gas, everyone clears the area on foot and upwind at once, nothing capped, spliced, or shut off by the crew, and the utility is called from a distance.

3. Set a permanent offset reference at every corner and end point before excavation can disturb the exact spot. Drive an offset hub a fixed, recorded distance back from the true corner, square to the run, so the corner can be re-found by measurement after the first hole is dug through it. Acceptance: two offset hubs per corner, each a stated and recorded distance back, at a right angle to each other, referenced to the confirmed corner from step 1. Wrong looks like marking the true corner with a single stake and nothing else, kicked loose or buried by the first shovel of spoil. Stop rule: a corner against a fixed obstruction that can't take two square offsets gets two offsets from different directions instead of one; no corner goes forward with only a single, unreferenced mark. Hazard: none.

4. String a taut mason's line between the corner references and correct for sag before trusting it as the working line. Pull tension by hand or a line tightener and sight or level down its length; hold sag under a quarter inch at midpoint on any span up to 100 ft. Acceptance: sag under a quarter inch at midpoint, confirmed by eye or a line level, on every strung span. Wrong looks like a string that looks straight standing at one end but is visibly bowed halfway down the run, quietly walking every mid-run post off the true line by the same amount. Stop rule: any bow or sag past a quarter inch gets a mid-span support, staked slightly off the true line so the support itself never becomes the reference, before any station is marked off that segment. Hazard: none.

5. Mark every post station from the fixed corner reference, never by measuring forward from the previous mark. Pull the tape from the corner hub for each station and mark independently; do not walk a story stick or scrap board from post to post, since a small error at each hop compounds by the far end of a long run. Acceptance: every mark within a half inch of its computed station, measured from the corner reference each time. Wrong looks like a run where the first six posts land dead on and the last three drift progressively further off, the signature of cumulative hop-to-hop error. Stop rule: any mark outside a half inch of its computed station gets re-measured before its hole is dug; the error is corrected at that mark, not spread across the remaining spacing to hide it. Hazard: none.

6. Probe every marked station to the post depth the setting procedure will need, and note grade change post to post. Push a soil probe or rod by hand at each mark to the required depth; record any refusal, rock, debris, or an unexpected feel, and note where the ground rises or drops enough to affect a stepped versus racked decision. Acceptance: every station probed clear to depth, or flagged with what stopped the probe and at what depth. Wrong looks like finding a rock ledge only when the auger stalls mid-hole on install day, after material has already been ordered to the station count. Stop rule: any station that refuses the probe before reaching required depth is flagged and held for step 7, never dug through blind. Hazard: the same struck-utility exposure as step 2 if probing pushes past the confirmed clear zone; probe by hand feel only, never drive hard past resistance, since resistance may be a shallow line rather than a rock, and the same clear-the-area response applies if anything is struck.

7. Resolve every flagged station by relocating the mark, and re-verify it still sits inside the property line and any adopted setback before it's accepted. Shift the mark clear of the obstruction, re-measure it from the corner reference like any other station, and check the shifted position against the line and the permit's setback, not just against neighboring posts. Acceptance: a relocated mark measured from the corner reference, confirmed inside the line and setback, shift distance and reason recorded next to the original station number. Wrong looks like nudging a post around a rock without rechecking whether the nudge puts it outside the line or inside a setback the permit doesn't allow. Stop rule: a flagged station that can't stay inside the line and setback does not get decided in the field; it goes back to the office for a design change first. Hazard: same as step 6, since resolving a flag still involves probing the new spot.

8. Walk the finished layout end to end with the crew lead who will run the digging, checking every station against the string line and the material plan's post count before the first hole opens. Confirm the mark count matches the material plan, that no flag from step 6 or 7 remains open, and that the string line is still taut and unmoved since step 4. Acceptance: crew lead sign-off recorded on the layout sheet, mark count matches the plan, zero open flags. Wrong looks like digging starting the same morning the layout crew finishes, with no second set of eyes on the marks. Stop rule: no independent walk and sign-off, no digging, regardless of how confident the layout technician is. Hazard: none.

The record this produces

One layout sheet per run: the corner source and verification method, the locate ticket number and date, both offset hub distances at every corner, the station list with each mark's distance from its corner reference, every obstruction flag and how it was resolved, and the crew lead's sign-off. It goes in the job file before the first post is set. The office reads it to confirm the material order matches the station count. A crew reset months later, after a heave or a rot complaint, reads it to know whether the layout was actually verified or a station drifted from day one.

Worked pass, with a step that failed

A 96 ft rear leg of an L-shaped residential wood privacy run, part of a 210 ft job with three corners and a gate near the driveway. Step 1: no current survey; the rear corner pin was found with a metal detector and verified against two other platted corners, both within an inch of the plat. Step 2: 811 ticket pulled four days ahead, marks fresh, well inside the 15-day window. Step 3: offset hubs set 3 ft back from each rear corner, square to the run. Step 4: string pulled taut corner to corner; sighted level, no visible bow across the 96 ft span, no mid-span support needed.

Step 5: stations marked at 8 ft centers from the corner reference, 0 through 96 ft, 13 posts, every mark independently taped from the hub and landing within a half inch of its computed station.

Stations run 1 through 12 at each 8 ft interval outward from the corner (station 1 at 8 ft, station 5 at 40 ft, station 12 at 96 ft); the corner post itself, at 0 ft, is fixed off the offset hubs from step 3 and isn't separately probed.

Step 6: probing found stations 1 through 4 clear to the required 32-inch depth. Fail. Station 5, at 40 ft, refused the probe at 8 inches, consistent with a rock shelf. Stop rule taken: flagged with the refusal depth noted, not dug through, held for step 7.

Step 7: the mark was shifted 14 inches toward the house to clear the ledge, re-measured from the corner reference at 41 ft 2 in, checked against the property line and the jurisdiction's adopted setback; the shift stayed well inside both, so it was accepted and logged with the shift distance and reason next to station 5.

Step 8: the crew lead walked all 13 posts against the layout sheet and the privacy plan's post count, confirmed station 5 was marked with its reason, found no other open flags, and signed off before digging.

References

• See related: fencecontractor-fence-line-tree-removal-prep, for clearing obstructions from a confirmed line
• See related: fencecontractor-post-setting-depth-and-concrete, which owns depth, diameter, and concrete technique once a station is marked
• See related: fencecontractor-shared-fence-neighbor-dispute-protocol and fencecontractor-residential-vs-commercial-fence-permit-process, for a contested line or the permit itself
• 811 / Common Ground Alliance state one-call requirements for utility locates before excavation
• Local zoning ordinance for setback distances, as adopted by the jurisdiction