The Short Version
The subcontractor relationship is where more margin gets lost than almost anywhere else in construction. Not because subs are dishonest — most aren't — but because builders hire them on trust and handshakes, skip the documentation, and then discover mid-job that scope is ambiguous, quality standards weren't communicated, and there's no written agreement to point to when something goes sideways. I've worked with builders who have strong relationships with the same subs for 10+ years and still get burned by a missed detail on a specific job. The documentation isn't about distrust — it's about clarity. And clarity protects the relationship as much as it protects the margin.
Sound Familiar?
Signs your subcontractor process has gaps:
- You've had a scope dispute with a sub and had nothing in writing to resolve it
- You've had a worker injured on your site and discovered the sub's workers' comp had lapsed
- You don't have signed subcontractor agreements — just verbal agreements or text messages
- You've been surprised by a sub's invoice amount because scope wasn't defined in writing
- You've had to redo sub work at your expense because quality standards weren't specified upfront
What We Found
The Four Documents Every Subcontractor Must Provide Before Starting Work
I require four documents from every subcontractor before they set foot on a jobsite. This is not negotiable, and communicating it clearly upfront is part of the professional standard you're setting for your company.
1. Certificate of Insurance (COI)
The COI must show current general liability insurance and workers' compensation coverage. Both must be in force — not expired, not pending renewal. The COI must list your company as an additional insured on the general liability policy. This is the piece most builders miss. Being an additional insured means the sub's GL policy extends to cover you for claims arising from the sub's work. Without it, a claim against the sub can become a claim against you directly.
The practical rule: get the COI before the sub starts. Set a calendar reminder 30 days before the expiration date to request a renewal certificate. A sub who won't provide current insurance is not a sub you want on your jobsite — regardless of how good their work is. Uninsured workers on your site are your liability.
2. Signed Subcontractor Agreement
The agreement defines scope (specifically — what is and isn't included), payment terms (how much, when, what triggers the draw), warranty obligations (how long, what's covered, what voids it), and quality standards (referenced spec documents, allowable tolerances, inspection requirements). It should also address what happens if the sub's work fails — who bears the cost of correction.
A good subcontractor agreement is 2–4 pages, not 20. The goal is clarity, not legal complexity. I've seen builders try to use elaborate contract templates that they don't fully understand and that their subs never read. A shorter, plain-language agreement that both parties actually read and understand is worth more than a comprehensive legal document that sits in a folder.
3. W-9
Required for 1099-NEC reporting at year-end. Any sub you pay more than $600 in a calendar year gets a 1099. Get the W-9 before the first payment, not in January when you're scrambling to file. Missing 1099s create IRS exposure — the penalty for willful failure is $570 per form as of 2026.
4. References from Recent Comparable Projects
For new subs, require two references — other GCs or builders who have used them on comparable work in the last 12 months. Call the references. Ask specific questions: Did they finish on schedule? Did they show up consistently? Were there quality issues? Would you use them again on a similar project? A sub who can't produce current references is telling you something.
The Subcontractor Onboarding Conversation Most Builders Skip
Documents alone aren't enough. Before a sub starts on a new project, have a 20-minute onboarding conversation that covers five things:
1. Scope walkthrough — Walk the scope in person or on a call. Even if the agreement is written, confirm both parties have the same understanding of what's included and what isn't. The disputes I see most often are not "they didn't do what the contract said" — they're "we had different interpretations of what the contract said." A conversation eliminates most of this.
2. Schedule expectations — When do you need them to start? When is the critical path milestone? What's the consequence if they miss it? Be explicit. "We need framing complete by the 15th because mechanical rough-in starts the 17th and we have a hard permit inspection on the 22nd" is more effective than "we need it done in two weeks."
3. Jobsite standards — What are your expectations for cleanup, communication, and daily progress reporting? If you're using JobTread for daily logs, tell them how you want conditions documented. If you have a specific end-of-day cleanup standard, say it now. Enforce it consistently and subs will meet it. Let it slide and they'll assume it's optional.
4. Change order process — How do you want to handle scope additions or conditions that differ from the contract? Verbal OKs that become invoice disputes are one of the most common sources of conflict between GCs and subs. Establish the rule: no additional work without written approval, and scope changes get priced and approved before the work happens — not after.
5. Payment process — When do you process draws? What documentation do they need to submit (lien waiver, invoice format, percent complete confirmation)? How long from submission to payment? Most subs have been burned by slow-pay GCs and will be relieved to hear a clear, specific answer. See also the post on lien waivers — your sub should be providing conditional lien waivers at each draw, and they need to know this from day one.
Building a Subcontractor Roster That Protects Your Schedule
One of the most expensive things in construction is discovering on a Thursday morning that your framer can't start Monday. Having a single-source dependency on any trade — one framer, one plumber, one electrician — means their availability problem becomes your schedule problem.
The roster strategy: for every trade you use regularly, identify and qualify at least two subcontractors who can do the work at your quality standard. You won't use both on every project, but having a vetted backup means a capacity conflict doesn't crater your schedule.
Building the roster isn't complicated. On every bid you send out, CC a second qualified sub. You'll get pricing data (useful for verifying your primary sub's bids are competitive) and you'll be building a relationship that you can activate when you need it. The builders I work with who have the most schedule predictability typically have 2–3 vetted options per major trade and rotate work between them based on availability and project fit.
Also worth noting: how you treat subs determines who picks up your calls when they're busy. Subs talk to each other. Being known as a GC who pays on time, communicates clearly, and doesn't change scope without a change order is a competitive advantage — you get the best subs, at better prices, with more schedule priority. The builders I've seen get the most from their sub relationships are the ones who treat the relationship like a long-term partnership and not a transaction to be optimized at every draw.
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Four documents minimum: a current certificate of insurance showing general liability and workers' compensation with your company listed as additional insured, a signed subcontractor agreement defining scope and payment terms, a W-9 for 1099 reporting, and references from recent comparable projects. Get all four before the sub starts — not after the first invoice arrives.
A subcontractor agreement should define scope in specific terms (what's included and what's not), payment amount and draw schedule, warranty obligations and duration, quality standards and references to any applicable specs, the change order process, cleanup and safety requirements, and what happens if the sub's work fails inspection or requires correction. Two to four pages of plain language beats a 20-page template that no one reads.
General liability insurance (minimum $1M per occurrence, $2M aggregate is standard for residential construction) and workers' compensation insurance if they have employees or if your state requires it for sole proprietors on commercial work. Your company should be listed as an additional insured on their GL policy. Request certificates of insurance and verify expiration dates — a lapsed policy creates liability that transfers to you.
Your first protection is the subcontractor agreement — specifically the section that addresses correction of defective work at the sub's cost. If the work fails your quality standard or an inspection, notify the sub in writing with photos and a clear description of what needs to be corrected. If the sub refuses or the correction is inadequate, you'll need to hire someone else and backcharge the original sub for the cost. This is only possible if you have a written agreement that addresses it. Verbal quality standards that aren't met create disputes with no clear resolution.
This is a legal classification question, not a preference — misclassifying employees as contractors is a significant IRS and state labor department risk. The IRS test looks at behavioral control (do you direct how the work is done?), financial control (do you provide tools and set hours?), and the type of relationship (is there a written contract, are benefits offered?). For true subcontractors who run their own businesses, control their own methods, and work for multiple clients, 1099 is appropriate. For workers you direct daily and who work exclusively for you, W-2 is almost certainly required. Consult your accountant if you're unsure — the penalties for misclassification are significant.
