Managing subcontractors is the hardest part of being a general contractor. Your subs are the ones doing the work, but you're the one responsible for the outcome. When they're great, your projects run smooth. When they're not, you're the one getting the 10pm text from the homeowner.

I manage 8-12 subcontractors per residential remodel. Plumbing, electrical, HVAC, framing, drywall, tile, painting, flooring, cabinets, countertops, roofing, landscaping. Each one runs their own business, has their own schedule, and has their own way of doing things.

Over the years, I've built systems for every stage of the sub relationship: finding them, vetting them, onboarding them, scheduling them, tracking their compliance, paying them, and -- when necessary -- firing them. This guide covers all of it.

Finding Good Subs (The Actual Hard Part)

Every GC says "I can't find good subs." What they really mean is "I can't find good subs who are available, affordable, and reliable." That Venn diagram has a very small center.

Where to Actually Find Subs

1. Other GCs. The best sub referrals come from GCs who do similar work in your area. This seems counterintuitive -- why would a competitor share their subs? Because good subs have capacity. They work for multiple GCs. And GCs who refer good subs to each other build reciprocal relationships. 2. Supply houses. Your local plumbing, electrical, and lumber supply houses know every sub in the area. The counter guys see who's buying materials consistently, who pays their bills, and who does volume. Ask them. 3. On the job site. When you visit other construction sites (permitted, obviously), pay attention to the quality of work. If a framing crew is doing clean work, get their card. If a tile installation looks perfect, find out who did it. 4. Sub-specific platforms. BuildZoom, Subcontractor.com, and even Craigslist can work for initial discovery, but ALWAYS vet before hiring.

What NOT to Do

  • Don't use the cheapest sub who answers the phone. The cheapest bid is the most expensive project.
  • Don't hire a sub without checking their license and insurance. One uninsured sub on your job site can cost you everything.
  • Don't assume a great residential sub can do commercial work, or vice versa.

Vetting Subs: The 5-Point Check

Before any sub touches your job site, verify these five things:

1. License Verification

Check their contractor's license with your state licensing board. In California, that's the CSLB website -- takes 30 seconds. Verify:

  • License is active (not expired, suspended, or revoked)
  • License classification matches the work (C-10 for electrical, C-36 for plumbing, etc.)
  • Workers' comp status (exempt or insured)

2. Insurance Verification

Request a Certificate of Insurance (COI) directly from their insurance company, not from the sub. You need:

  • General Liability: $1M per occurrence minimum (your contract may require $2M)
  • Workers' Compensation: Statutory limits (unless they're a sole proprietor in a state that allows exemption)
  • Your company listed as Additional Insured on their GL policy

Important: verify the policy is active by calling the insurance company. Subs have been known to provide COIs for cancelled policies.

3. Reference Check

Call 2-3 GCs they've worked for. Ask specific questions:

  • Did they complete the work on the agreed timeline?
  • Did they stay within the quoted price or were there surprise extras?
  • How did they handle punch list items?
  • Would you hire them again?

The last question is the only one that really matters.

4. Financial Stability

A sub who's about to go out of business is a sub who might file a mechanics lien on your project. Red flags:

  • Asking for large deposits or advance payments
  • Unusually low bids (buying work to keep cash flowing)
  • Complaints about not getting paid on other jobs
  • Can't provide a W-9

5. Work Quality

Visit a current or recent job site. Look at:

  • Cleanliness and organization
  • Quality of workmanship up close
  • How they interact with other trades
  • Whether their crew is professional and properly equipped

Onboarding a New Sub

Once a sub passes your vetting, onboard them properly. This takes 30 minutes and saves hours of problems later.

The Onboarding Checklist

  • Signed subcontractor agreement (scope expectations, payment terms, insurance requirements, dispute resolution)
  • W-9 on file
  • COI verified and uploaded
  • Workers' Comp certificate verified and uploaded
  • License number verified
  • Emergency contact info
  • Portal access set up (send them their unique link)
  • Payment method preferences (check vs. ACH)
  • Communication preferences (call, text, email, portal)

The key: do this ONCE, keep it updated, and never start a new project with a sub whose documents have expired.

In Opsite, all of this lives in the Compliance Hub. When a sub's insurance is 30 days from expiring, they get an automatic notification. When it expires, new POs are blocked until they update it. No manual tracking, no spreadsheet of expiration dates.

The Purchase Order System

Every dollar you pay a sub should be tied to a purchase order. No exceptions.

Why POs Matter

Without POs:

  • "I thought the price was $8,000" -- "No, I said $10,000"
  • "That wasn't in my scope" -- "Yes it was, we discussed it"
  • "You owe me for that extra work" -- "What extra work?"

With POs:

  • Scope is written and signed
  • Price is agreed before work starts
  • Changes require a PO amendment (also signed)
  • Payments are tracked against specific POs
  • At year-end, you know exactly what each sub earned (hello, 1099s)

What a Good PO Includes

  • Scope of work -- specific description of what's included and what's NOT included
  • Contract amount -- lump sum or time & materials with a not-to-exceed
  • Payment terms -- when payment is due (upon completion, upon inspection, etc.)
  • Timeline -- expected start and completion dates
  • Special conditions -- site-specific requirements, cleanup expectations, warranty terms

    • PO Amendments

    When the scope changes (and it always changes), create a PO amendment:

    • Reference the original PO number
    • Describe the additional/changed scope
    • State the additional cost
    • Get the sub's signature before the work starts

    This is non-negotiable. The amendment protects both you and the sub.

    Scheduling Subs Across Multiple Jobs

    This is where most GCs lose their minds. You have 8 active jobs, each with 5-10 subs who need to show up in a specific sequence. Plumbing rough before drywall. Drywall before paint. Paint before floors. One delay cascades everywhere.

    The Scheduling Rules

    1. Build in buffer. If your plumber says "3 days," plan for 4. If your drywall crew says "a week," plan for 8 days. Subs are optimistic about timelines. Always. 2. Confirm 48 hours ahead. Call or text every sub 48 hours before their start date. "Hey, we're on track for your Wednesday start at Oak Street. Still good?" Half the scheduling problems come from subs who forgot or overcommitted. 3. Have backup subs. For your critical trades (plumbing, electrical, drywall), maintain relationships with at least 2 subs. When your primary can't make it, you have someone to call. 4. Communicate delays immediately. When one sub falls behind, notify everyone downstream the same day. Don't wait until they show up and find the site isn't ready. That burns trust and wastes their time. 5. Track it visually. Whether it's a Gantt chart, a whiteboard, or a software tool, you need a visual view of who's on which job and when. Keeping it in your head works until it doesn't -- and when it fails, it fails catastrophically.

    Paying Subs: Speed Builds Loyalty

    The number one thing you can do to keep good subs is pay them fast. Good subs have options. They'll prioritize the GC who pays in 7 days over the one who pays in 30.

    The Payment Process

  • Sub completes their scope (or a defined milestone)
  • You inspect the work
  • Sub submits a payment request (through the portal or however you handle it)
  • You verify the amount against the PO
  • You process payment within 3-5 business days
  • Sub provides a lien waiver

    • Lien Waivers Are Non-Negotiable

    Every payment to a sub should come with a lien waiver:

    • Conditional waiver -- submitted with the payment request ("I waive lien rights upon receipt of $X")
    • Unconditional waiver -- submitted after the check clears ("I confirm receipt of $X and waive all lien rights for this payment")

    Skip this step, and you risk a sub filing a mechanics lien against the property -- even after you've paid them. I've seen it happen. It's a nightmare for everyone.

    When to Fire a Sub

    Not every sub relationship works out. Here are the signals that it's time to move on:

    • Repeated no-shows without communication
    • Quality issues that persist after one clear conversation
    • Insurance lapses they won't fix
    • Scope creep -- constantly claiming work is "extra" when it's clearly in the PO
    • Safety violations on your job site
    • Financial distress -- asking for advances, bounced checks from them to suppliers

    When you fire a sub mid-project:

  • Document the reason in writing
  • Pay them for completed work (per the PO)
  • Collect lien waivers for all payments made
  • Have your backup sub ready to step in
  • Notify your client about the timeline impact

    • Don't burn bridges unnecessarily. Construction is a small world. But don't keep a bad sub on your team out of fear of the transition -- the longer you wait, the worse the damage.

    The Technology That Makes This Manageable

    Everything I've described above is manageable with spreadsheets, phone calls, and a filing cabinet. But "manageable" means spending 2-3 hours every night on admin instead of being with your family.

    I built Opsite specifically to solve these problems:

    • Sub portal with no login required, bilingual (English/Spanish) -- subs view POs, request payments, upload compliance docs
    • Compliance Hub with automatic expiration tracking and alerts
    • Purchase orders with digital signatures and amendment tracking
    • Payment queue with compliance verification before any check goes out
    • Lino (AI assistant) that can tell you "which subs have expiring insurance" or "what's my total outstanding to subs across all jobs" in plain English

    Starting at $349/month. No per-user fees. Your subs access the portal for free.

    Bar Benbenisty is a licensed general contractor in California and the founder of Opsite. See the sub portal in action

    Disclaimer: This article is for general informational purposes only and does not constitute legal, financial, or professional advice. Lien waiver requirements, licensing rules, insurance obligations, and compliance standards vary by state and jurisdiction. Always consult a licensed attorney, insurance professional, or accountant for advice specific to your situation. Opsite is a software platform and does not provide legal or financial advisory services.