Pile Elevation Verification Workflow Solar Construction

Before walking through the step-by-step procedure, it is important to understand the two fundamentally different workflow models that solar contractors use — because they produce dramatically different results on project schedule.

Before the GPS rover operator arrives on site, the following setup must be completed in the verification system:

1. Import the design elevation file. The EPC or racking manufacturer provides a spreadsheet or CSV file with every pile ID and its design cutoff elevation. Import this file into Sitemark — the design elevations are now pre-loaded for every pile ID. Field crews will never manually enter design values. Confirm the pile ID naming convention matches the EPC file exactly.
2. Configure tolerance per block. Enter the EPC-specified tolerance for the project — typically ±0.02 ft vertical. If different blocks have different tolerance requirements (fixed-tilt vs. single-axis tracker areas), set tolerance per block individually.
3. Verify GPS equipment calibration. Before the first measurement day, perform a calibration check: measure a known benchmark elevation with the GPS rover and confirm the measured elevation matches the known elevation within the instrument's specified accuracy. Log this calibration record in the system.
4. Confirm CORS network coverage or deploy base station. For most project sites, check that the CORS network (e.g., NGS CORS, state DOT network) provides adequate coverage for RTK fixed solution across the site. For remote sites outside network coverage, set up a portable base station on a known benchmark point. See our guide on GPS rover setup for solar pile verification.
5. Brief the field crew. The GPS rover operator should understand: how to confirm fixed RTK solution before logging a measurement, the correct placement of the rover tip at pile cutoff (not on top of a bent pile cap or irregular cut), and how to flag and photograph failed piles for the corrective action record.

Each measurement day begins with the following equipment startup procedure:

1. Power on the GPS rover and wait for satellite acquisition. Allow 3-5 minutes for the rover to acquire satellites and establish communication with the RTK correction source (base station or network). Confirm the solution status shows "Fixed" — not "Float" or "Single."
2. Check on a known benchmark. Measure a control point whose elevation is known from the project control network. The measured elevation should be within ±0.02 ft of the known value. If the discrepancy exceeds 0.02 ft, investigate before logging any pile measurements — do not assume the GPS is correct.
3. Log the calibration check in the verification app. Record the benchmark ID, known elevation, measured elevation, and difference. This becomes part of the calibration record attached to the day's measurements in the EPC package.
4. Confirm project and block assignment. In the app, confirm you are logging to the correct project and the correct block. On multi-block sites, logging measurements to the wrong block is a common error that requires significant cleanup time.
5. Pair the rover to the app via Bluetooth (if using direct GPS integration). When the rover is paired to the Sitemark app, a single tap logs the pile ID and elevation simultaneously from the rover — no manual elevation entry. This is faster and more accurate than reading the elevation from the rover display and typing it manually.

For each pile, the measurement procedure is:

1. Approach the pile and confirm its pile ID. The pile ID is typically staked, painted, or marked during driving. Confirm the ID matches the design file — do not assume pile positions are correct based on location alone, especially near the ends of rows where driving sequences can shift.
2. Place the rover tip at the pile cutoff elevation. The measurement point is the top of the pile — the cut or sawed surface. On steel H-pile or pipe pile, place the rover antenna phase center marker directly on the pile cap, ensuring the pole is vertical. Do not place on a bent flange, a slag deposit, or a temporary cap that adds height above the actual cutoff.
3. Wait for fixed RTK solution confirmation. The rover display or connected app must show "Fixed" before logging the measurement. If solution drops to Float while you are at the pile, wait for it to recover — do not log a Float measurement as a pile elevation record.
4. Log the measurement. In the Sitemark app, select the pile ID and tap to capture the elevation. Pass/fail is calculated and displayed immediately. If the pile is within tolerance, move to the next pile. If the pile is outside tolerance, photograph the pile, note the condition (soil heave, hard driving refusal, bent pile), and flag it for corrective action.
5. For failed piles: create the corrective action record immediately. Do not wait until end of shift. Create the corrective action record now with the failed elevation and the condition note. Notify the pile driving foreman while the rig is still accessible. A re-drive initiated immediately is 10 times cheaper than an emergency call-back the next day.

Failed pile management is the most documentation-intensive part of pile verification — and the most common source of EPC package rejection. Here is the correct procedure:

At the end of each verification day, generate a daily progress report from the Sitemark dashboard. This report serves two purposes: (1) it gives the project manager visibility into which blocks are progressing toward EPC sign-off readiness, and (2) it provides the EPC project coordinator with a status update so they can schedule their engineer for package review as blocks approach completion.

The daily progress report should show: blocks active today, piles verified today by block, piles remaining by block, failed piles and corrective action status, and an estimated completion date for each active block based on current verification rate. Share this with the EPC coordinator weekly at minimum — EPCs appreciate advance notice that a block sign-off package is coming so they can have their engineer available for same-day review.

When a block reaches 100% verification with all corrective actions closed, the EPC sign-off package is ready. In Sitemark, this is a one-tap operation:

1. Select the completed block in the dashboard.
2. Tap "Generate EPC Package." The system compiles the as-driven pile elevation report, block conformance summary, corrective action log, and calibration records into a single PDF.
3. Review the package — spot-check 5-10 piles, confirm the corrective action section is clean, confirm the calibration records are attached.
4. Email the package to the EPC project engineer directly from the app. The email is timestamped in the system for audit purposes.
5. Log the EPC sign-off when received. When the EPC issues written authorization for racking installation in the block, log the authorization date and the EPC engineer's name in the system. This closes the block documentation chain.

The goal is to submit the package the same day the block driving is complete — ideally before 5:00 PM so the EPC engineer can review it that evening and issue authorization before your racking crew mobilizes the next morning.