The Pre-Construction Documentation RFP: What to Put in Writing Before the First Flight

A pre-construction drone flight is not a line item. It's a piece of evidence that has to stand up in a meeting six months from now when someone's change order is on the line and nobody can remember what the site looked like on day one. The flight itself is the cheap part. The hard part is making sure the data behind it is scoped, signed, and stored in a way that survives the dispute it was meant to prevent.

Most RFPs get this wrong. They describe a deliverable, not an evidence chain. Here's what to put in writing before the first drone touches the site.

The deliverable isn't the photo — it's the metadata

A pilot flies a site, captures imagery, processes an ortho, hands the contractor a GeoTIFF. Looks done. Looks easy. Looks like a clear deliverable.

The thing that actually settles a change-order dispute isn't the GeoTIFF. It's the chain of custody behind the GeoTIFF: the flight log, the GPS coordinates, the EXIF timestamps, the ground control point coordinates, the processing parameters, the file hash, the storage location, and the date the data was delivered. Strip the metadata and you have a pretty picture. Keep the metadata and you have proof.

That's why the right line item in an RFP isn't "drone flight and ortho." It's "timestamped, georeferenced pre-construction documentation with metadata chain of custody and archive." The verbiage matters because it tells the pilot and the legal team what the data is for, not just what it shows.

What to include in the deliverable specification

A pre-construction documentation flight is worth scoping out the same way you'd scope a survey. Here's the checklist that goes into a working RFP:

Flight plan and execution

• Site boundary defined (KMZ, shapefile, or annotated PDF)
• Target ground sample distance (GSD) — usually 0.5–1.0 inch/pixel for ortho work, 2–3 cm for volumetric baseline
• Required overlap (front lap and side lap) — 80/70 minimum for vegetation or complex terrain, 75/65 for clean urban sites
• Weather window and contingency clause
• Time of day — golden hour isn't a creative preference; long shadows in winter throw off photogrammetry alignment

Control and accuracy

• Number and placement of ground control points (GCPs) — typical layout is 5 GCPs per 10–17 acres, four perimeter corners plus a center support, with RTK/PPK base station logging for 2+ hours where the CORS baseline exceeds ~60 miles
• Target accuracy — absolute horizontal and vertical RMSE in pixels or centimeters
• Coordinate system and projection — modified state plane, standard state plane, or local grid
• Datum — NAD83(2011) is the Colorado standard; verify with the project surveyor

Deliverable format

• Ortho map — high-resolution GeoTIFF, georeferenced, with a world file (.tfw) and metadata sidecar
• Photo inventory — timestamped JPEGs with full EXIF (camera, exposure, GPS, timestamp) preserved, organized by location
• 3D model — point cloud (.las or .e57) and mesh (.obj or .fbx) for VDC teams
• PDF report — executive summary, key images, site plan overlay, metadata log
• Optional: video walkthrough, flythrough, or 360 interior documentation

Chain of custody

• Storage location and retention period
• File hash (SHA-256) for tamper evidence
• Delivery method and confirmation of receipt
• Date the baseline becomes the "as-constructed" reference

The point of putting this in the RFP isn't paperwork. It's that six months from now, when the change order hits, you can hand the file to opposing counsel and watch the conversation end. The contractor who specs this at bid time is the contractor who wins disputes at closeout.

What the case studies on the Wet Dog Drones site actually demonstrate

Three projects on the site, all real, all with differentiators worth understanding before you write your own RFP:

Severance Library — the $40,000 case. A city tried to bill the contractor $80,000 for road damage claimed to have happened during construction. Pre-construction orthos showed the roads were already damaged before mobilization. The change order split 50/50. The contractor's avoided exposure: $40,000. Lesson: a road condition baseline protects a contractor from a third party (the city) when the third party's claim is "your trucks did this." (See the Severance Library case study for the full timeline.)

Clear Creek Schools — the $400,000 case. Halfway through the project, the owner filed a $400,000 change order claiming the contractor had stripped copper and radiators from the building. Interior documentation — captured before crews arrived — proved the building was already empty. The change order was killed. Not negotiated. Killed. Lesson: interior documentation protects a contractor from the owner when the owner's claim is "your people stole this." (See the Clear Creek Schools case study.) Note: a more detailed narrative of the same case lives in The $400,000 Photo — Michael's first-person account of the dispute, including the meeting where the documentation closed the room.

The 16-month case. Bi-weekly progress flights on the same project — Severance Library was both a pre-construction dispute and a long-arc monitoring engagement, documented over 16 months and condensed into an 85-second time-lapse. The pre-construction flight is flight zero; every bi-weekly flight after that is measured against it. Lesson: the pre-construction flight is the seed of a recurring monitoring deliverable, not a one-shot. (See the Severance Library case study for the full project — both the $40K road-damage dispute and the 16-month build timeline.)

Add the year total: $440,000 in documented savings across the two projects above. That's the number the work is anchored to. (Severance $40K GC-avoided + Clear Creek $400K avoided = $440K year-total. The Severance Library project also produced a 16-month bi-weekly progress flight set + an 85-second time-lapse, but that's a recurring-monitoring deliverable, not a one-time savings event.)

Three things the RFP has to say that nobody thinks about

1. Who owns the data, and what's the license. A pre-construction baseline is a record of fact. The contractor should own the data, with a perpetual license to the GC and the owner. If a subcontractor on the project flies their own documentation, the data ownership and license terms need to be on paper before they take off. The dispute this prevents is the one where the owner wants the ortho and the third party has the only copy.

2. What happens to the data when the project closes. A pre-construction ortho is a legal document, not a marketing asset. The retention period should be defined (typical: 7 years for statute-of-limitations protection on construction defect claims; longer for public projects). Where is it stored? Who has access? Can it be retrieved five years from now when the warranty dispute lands?

3. The integration with the contract documents. The pre-construction flight is an early-fee item that the GC is paying for. It should be referenced in the prime contract as the baseline for any change order claim involving existing conditions. That single line in the contract documents is what turns the ortho from "a piece of paper" into "a contractual reference point." Without that contract clause, a contractor can hand the owner the ortho and the owner can still say "this isn't relevant to my claim."

The trap with sub-contracted drone providers

National aggregators market pre-construction documentation as a feature. What they typically deliver is an ortho, a PDF, and a storage link. That's the same package a local Part 107 operator delivers — but with three structural differences worth knowing:

• Local operator is on-site or on-call. A Denver Front Range GC can get a baseline flight flown in 48 hours when a dispute is brewing. A national aggregator schedules based on their route. Speed matters when the issue is "the city is sending a letter in two weeks and we need a baseline right now."
• Local operator carries commercial insurance tied to the state. Aggregate general liability and aviation insurance are checked at the policy level, not the marketing level. Worth asking for the certificate of insurance before the flight.
• Local operator is accountable to the same legal jurisdiction as the project. A national aggregator's arbitration clause can move the dispute venue. A local operator's contract is enforceable in the same county as the project.

The right line in the RFP: "Provider must be FAA Part 107 certified, carry commercial aviation insurance, and operate within driving distance of the project site."

Bottom line: don't spec a photo. Spec an evidence chain. The metadata is the deliverable — the photo is just the part you can see.

Sources & further reading

• Wet Dog Drones case studies: Severance Library · Clear Creek Schools
• Wet Dog Drones resources: Pre-Construction Site Documentation as Risk Mitigation · Resolving Earthwork Disputes with Drone Volumetric Analysis
• Wet Dog Drones blog: The $400,000 Photo (Michael's first-person account of the Clear Creek dispute) · The Day Drone Data Saved the Wall
• Related services: Full Services Overview · 3D Modeling & Visualization · Volumetric Analysis