Most tower subcontractor vetting happens backwards. A GC gets a quote, the number looks fine, the sub says they're "fully insured and certified," and the paperwork gets chased down after award — sometimes after the crew is already on site. That order of operations is how a GC ends up holding the risk for a subcontractor's missing coverage or an undocumented climb.

This is the checklist we'd want a GC to run on us, written from the other side of the table. It's organized in the order we think it actually matters: insurance first, because it's the thing that protects you if something goes wrong; certifications and safety program second, because they're what prevents something from going wrong in the first place; then documentation, references and operational fit.

1. Insurance — get the certificate before the quote comparison, not after

A certificate of insurance (COI) is a five-minute ask that tells you more than almost anything else on this list. At minimum, confirm:

  • General liability limits — per-occurrence and aggregate. Tower work carries real third-party risk (dropped tools, equipment damage, site access incidents), so a sub running minimal GL limits is a red flag regardless of how good their crew looks on paper.
  • Umbrella or excess liability — a separate layer above the base GL policy. On larger scopes, this is often what a prime contract or landlord insurance requirement actually calls for.
  • Workers' compensation — statutory coverage plus employer's liability limits. This matters doubly in tower work: if a sub doesn't carry workers' comp and a climber is hurt, liability can flow upward to the GC.
  • Commercial auto liability — covers the fleet moving people, material and rigging between sites.
  • Additional insured status and waiver of subrogation — ask whether the sub's policy can add you as an additional insured and waive subrogation rights. A sub that balks at this, or can't get their broker to confirm it quickly, usually isn't carrying the coverage they claim to.

Request the actual COI, not a verbal confirmation of limits. A legitimate subcontractor can produce one within a day, because it already exists — it isn't something that gets created for your request.

2. Certifications — ask what the climbing crew holds, not just the company

"Certified crews" is a marketing line until you ask which certifications, held by whom. The baseline worth confirming for any crew member who climbs or works near structural hazards:

  • OSHA-10 for crew members, OSHA-30 for site leads — the standard baseline for construction safety training, and a reasonable floor for anyone running or working a tower site.
  • Authorized climber and rescue training to ANSI/ASSP Z359 — the fall protection and rescue standard. A crew without rescue-trained personnel on site has no self-rescue capability if something goes wrong at height, which means waiting on an external rescue response.
  • Qualified rigger and signal person training per ANSI/ASSP A10.48 — the construction/demolition operations standard for the telecommunications tower industry, covering rigging plans, lift procedures and signal person responsibilities. Any lift beyond basic hand-carried material should have a qualified rigger involved.
  • RF awareness and exposure safety (FCC OET-65) — relevant on any co-located site where other carriers' antennas may be transmitting during the work.
  • Current First Aid / CPR / AED — basic, but worth confirming it's current, not expired.

Ask for this at the individual crew level for the team actually assigned to your site, not a generic statement about "our certified workforce." A sub that can name the certifications their specific crew holds, unprompted, is usually the one that actually tracks it.

3. Rigging plans and site-specific safety documentation

For any lift beyond simple hand-carried material, ask whether the sub produces a written rigging plan under ANSI/ASSP A10.48 before the lift — covering load weights, rigging configuration, lift sequence and the qualified rigger's sign-off. Ask to see a sample (with client-identifying details redacted if needed) before award, not after.

Separately, confirm a site-specific job safety analysis (JSA) is standard practice before any climb — not a generic company-wide safety manual, but a document that reflects the specific site's hazards: structure condition, co-location/RF exposure, weather, access.

If the scope includes decommissioning or any lift sequence that isn't straightforward erection, ask specifically how the sub plans a tear-down or removal sequence. A tower losing sections loses stiffness and load path as it comes down — a sub that treats this the same as erection run in reverse, without re-engineering the lift sequence for the structure's reduced stability, is one worth questioning further. See our rigging plan guide for what to look for in the document itself.

4. Closeout documentation — ask what you get back, before the job starts

This is the item GCs most often skip asking about until the job is finished and they're missing something they need for their own closeout to the carrier or tower owner. Before award, confirm what the sub's standard closeout package includes:

  • Photo documentation tied to the actual work performed, not generic site photos
  • As-built records (antenna position vs. RF data sheet, torque logs, foundation/anchor records as applicable to the scope)
  • Sign-off documentation for the specific scope completed

A sub who can describe their closeout package specifically and consistently, without having to check with someone else, is usually a sub who actually runs this process on every job — not just when a client asks for it. For a full breakdown of what should be in this package, see what's actually in a tower closeout package.

5. References and operational fit

References matter less for whether the sub *can* do the work — most subs in this space can point to completed jobs — and more for how they operate day to day: do they communicate proactively when something on site doesn't match the drawing, or do you find out after the fact? Do they show up with the crew size they quoted? Ask a reference specifically about change management and communication, not just "were you happy with the work."

Operational fit also means confirming the sub can work inside your MOP and reporting format rather than running their own process in parallel. A sub who pushes back on using your safety program, your daily reporting format or your site access procedures is signaling friction before the job even starts.

6. Put it together before you compare price

None of this is unusual to ask for — it's what prequalification platforms like Avetta and ISNetworld already require, in one form or another, for subs working on carrier and utility sites. The difference is doing it before comparing bids, not after choosing the lowest number and discovering gaps during mobilization.

A subcontractor who has this paperwork ready — current COI, named crew certifications, a sample rigging plan, a described closeout package — isn't necessarily the cheapest bid, but is usually the one that doesn't turn into a change order or a liability conversation six weeks into the job.

Working this checklist against a potential sub for an upcoming scope? Request our crew availability and documentation package — COI, certifications, a rigging plan sample and our standard closeout format are ready to hand over before you've finished comparing bids.