Here's the thing about managing subcontractors: nobody teaches you how to do it. You figure it out by getting burned.
You pay a framer before getting a lien waiver — and he disappears with a mechanics lien on your client's property. You hire a plumber with expired workers' comp — and his guy gets hurt on your site. You forget to track a sub's insurance renewal — and find out six months later that you've been exposed the whole time.
If you want to know how to manage subcontractors without losing sleep (or losing money), this guide covers the fundamentals and the automation that makes it survivable at scale.
The 4 Things That Actually Matter in Sub Management
Strip out the noise and it comes down to four things:
- Compliance — Are their insurance and license current?
- Communication — Do they know what's expected?
- Payments — Are you paying them right, with documentation?
- Documentation — Can you prove everything if something goes wrong?
Most GCs have a loose handle on all four. The best GCs have systems that run them automatically.
Compliance: The One That Bites You Hardest
Let's start here because this is where the lawsuits come from.
Before a sub ever sets foot on your site, you need:
- General Liability (GL) insurance — with your company listed as additionally insured
- Workers' Compensation — required if they have employees, even in "no fault" states
- Contractor's license — verify it's active, not suspended
- W9 — you're required to 1099 any sub you pay over $600/year
These aren't nice-to-haves. If a sub's employee gets hurt on your site and that sub doesn't have WC, the claim can come back to your policy. If a sub files a mechanic's lien and you didn't get a lien waiver before paying, you're holding the bag.
The Problem With Spreadsheets
Most GCs track compliance in a spreadsheet. A column for each sub, a cell with the expiry date, a reminder to themselves to check it before each payment.
This falls apart fast. You've got 12 active subs across three jobs. That's 48 expiry dates to track (GL, WC, License × sub × renewal date). You forget to check. A sub renews but sends the cert to an old email. Six months pass. Now you've been working with an uninsured sub and didn't know.
What Automated Compliance Looks Like
Opsite tracks GL insurance, workers' comp, license, and W9 for every sub automatically. You upload the docs once. The system extracts the expiry dates. It emails the sub 30 days before anything expires. It shows you a compliance dashboard so you can see at a glance which subs are green, which are expiring, and which are lapsed.
Most importantly: it won't let you approve a payment to a non-compliant sub without flagging it first. You can override — but you have to consciously decide to, which means you're making an informed choice, not an accidental one.
For a deeper dive on what happens when insurance lapses mid-project: What Happens When Your Sub's Insurance Expires Mid-Job
Communication: Set Expectations Before Work Starts
Most sub disputes come down to one thing: misaligned expectations.
"I thought that was included in my scope." "I didn't know I was responsible for cleanup." "Nobody told me the inspection was Thursday."
The fix is documentation before work starts, not arguments after.
The Purchase Order Is Your Friend
A signed Purchase Order (PO) is the sub equivalent of a client contract. It specifies:
- Scope of work (detailed, not "framing")
- Contract amount
- Payment schedule
- Start date and expected completion
- Any special conditions (debris removal, working hours, etc.)
When a sub signs a PO, there's no ambiguity. If they come back saying "that wasn't in my scope," you open the PO. End of conversation.
Opsite has a full PO system — create a PO with line items, send it to the sub via email with a link to review and sign digitally. No printing, no scanning, no chasing. Amendments get sent the same way.
Keep Communication in One Place
The worst thing you can do is manage sub communication across text, email, and verbal conversations simultaneously. Important things get lost. You can't reference the thread when there's a dispute. "I texted him about it" is not a paper trail.
Use a tool that logs communication per job. Opsite has a messages thread at the job level — you can message subs directly and have a searchable history of every conversation tied to the project.
Payments: Right Way, Right Documentation
Paying subs seems simple. It's not. There's a right way and a wrong way, and the wrong way creates legal exposure.
The Right Way to Pay a Sub
Before you release any payment, this checklist should be complete:
- Insurance is current (GL + WC)
- PO is signed and in your records
- Work has been inspected (if applicable)
- Lien waiver has been generated and signed
A lien waiver is a legal document where the sub (or material supplier) waives their right to file a mechanic's lien against the property for the amount being paid. Without it, you can pay a sub and still have them file a lien later claiming they weren't paid. It happens.
Opsite auto-generates conditional or unconditional lien waivers based on payment type. The sub signs digitally. The signed PDF gets stored automatically. Before you can approve a payment, the system runs through the pre-payment checklist — insurance, PO, inspections, lien waiver — and flags anything missing.
More on lien waivers: California Lien Waiver Guide
Track What You've Paid
Every sub payment should be logged with method (check, ACH, wire, credit card), date, amount, and what it was for. This matters at tax time (1099s), in disputes, and if a sub claims they weren't paid for something they were.
Opsite logs every payment, syncs to QuickBooks as a bill, and gives each sub a portal to see their payment history — which eliminates "I never got paid for that" conversations.
Documentation: Your Protection When Things Go Wrong
Construction has disputes. Even on great projects with great subs. What determines who wins usually isn't who was right — it's who has the documentation.
What You Need to Document
- Signed POs and amendments
- Signed lien waivers for every payment
- Compliance docs (insurance certs, license numbers)
- W9s for every sub you pay over $600
- Inspection records
- Change orders that affected sub scope or payment
Daily Logs Protect You Too
A daily log that notes which subs were on site, what work was performed, and any issues that arose is worth its weight in gold if a dispute ever goes to arbitration or court. "Our logs show the framing crew was on site for 14 days" is a lot more credible than "I think it was about two weeks."
Opsite makes daily logs fast — you can speak for two minutes and the AI creates a structured log. Or you can upload job site photos and videos, and the AI analyzes them to generate the log automatically, including action items detected from the images and audio.
Building a Sub Roster That Actually Works
The GCs with the least sub headaches have spent years building a reliable roster. A few things that help:
- Vet before you need them — Don't call a new plumber when your regular one is booked. Build relationships when there's no deadline pressure.
- Give consistent subs consistent work — Subs prioritize GCs who keep them busy. If you throw them a bone every few months, they'll prioritize someone else.
- Pay fast, pay fairly — Reputation spreads. Subs talk. Being known as a GC who pays on time and doesn't nickel-and-dime is worth more than any vendor discount.
- Get their compliance docs before day one — Make it a non-negotiable part of onboarding. "We can't put you on a job until we have your GL cert and WC policy." Subs who've worked with professional GCs before won't blink.
Frequently Asked Questions
How do I keep track of subcontractor insurance?
The manual way: spreadsheet with expiry dates and calendar reminders. The automated way: software like Opsite that tracks GL, WC, license, and W9 for each sub, sends them renewal reminders, and shows you a compliance dashboard at a glance.
What is a lien waiver and why does it matter?
A lien waiver is a legal document where a sub waives their right to file a mechanic's lien against the property for the amount being paid. Without it, you can pay a sub and still be exposed to a lien claim later. Get a signed lien waiver before every payment.
Do I need a W9 from every subcontractor?
Yes. If you pay any sub more than $600 in a calendar year, you're required by the IRS to file a 1099. You need a W9 to do that. Collect it before the first payment, not at year-end when nobody can find it.
How do I handle a sub who always has excuses?
Documentation and leverage. If their work quality or reliability is a problem, document it in writing (emails, not texts). Hold payment for incomplete or defective work and have the back charge provision ready in your PO. The best move is replacing unreliable subs — good ones exist.
What's the difference between a PO and a subcontract?
A subcontract is a full legal agreement governing the entire relationship. A PO is a specific order for a specific scope of work with a specific price. For most trade work, a detailed PO with clear terms serves most GCs well. For large or complex engagements, a formal subcontract is better. Consult an attorney if you're unsure.
This guide reflects general best practices and is not legal advice. Consult an attorney familiar with construction law in your state for specific guidance.