You're an Interest-Free Loan to the GC: Subcontractor Cash Flow Survival

The single sharpest summary of subcontractor economics I've read came from a r/Construction post:

"Everyone has cash flow issues. Being a sub, you're an interest-free loan to the GC with little leverage to get paid quickly."

That's the whole game. Subs fund the GC's working capital. The GC uses your money for 60-90 days. Then they pay you. You absorb the cost of capital. The GC keeps the spread.

This post is about why that's structural, what leverage you actually have, and how the smartest subs play the game.

Why the GC system was designed this way

It's not personal. The general contractor system is built so that:

1. The owner pays the GC monthly based on percent complete
2. The GC marks up sub costs 5-15% (their margin)
3. The GC waits to pay subs until after they receive the owner's payment
4. The GC holds retainage from subs until project completion
5. The GC's working capital cost is effectively zero

You finance steps 3 and 4. The GC charges interest in the form of markup. You don't see your share.

The math: a 60-day delay in payment at a 12% cost of capital is roughly 2% of the contract value. On a $500K project, that's $10,000 of financing cost you're absorbing. Across an annual revenue of $3M, that's $60K of margin going to support the GC's working capital.

The "leverage" you actually have

Subcontractors have less leverage than they think — but more than they use. The actual tools:

1. Prompt pay statutes (state-specific, real teeth)

Most states have prompt pay laws that require GCs to pay subs within a defined number of days after receiving payment from the owner. Common defaults:

• 7-15 days from GC receipt of owner payment (private projects)
• 5-10 days (public projects, often with statutory interest if violated)

States with strong prompt-pay enforcement: California, Texas, Florida, New York, Pennsylvania, Illinois, Washington.

The leverage: a written demand citing the specific statute usually accelerates payment without requiring litigation.

2. Mechanics lien rights (powerful, time-sensitive)

A mechanics lien attaches to the property for unpaid work or materials. It clouds the title and prevents resale or refinancing until satisfied.

Critical timing rules vary by state:

• California: Preliminary 20-day notice required, lien filing within 90 days of completion
• Texas: Pre-lien notice by 15th of month following work, lien filing by 15th of 4th month
• Florida: Notice to owner within 45 days, lien filing within 90 days

Lien rights are usually the most powerful collection tool you have. Most subs forfeit them by not filing preliminary notices on time.

3. Joint check agreements (preventive, requires negotiation upfront)

A joint check agreement requires the GC to issue payment as a check made out to both you and your supplier. Benefits:

• Suppliers extend you better terms because they're not relying on your credit
• You can't accidentally use supplier money for other purposes
• Suppliers won't lien the project

Get joint check agreements set up at contract execution, not after problems arise.

4. Bonding rights (last resort, requires payment bond)

On projects with payment bonds (most public projects, many large private), unpaid subs can claim against the bond. Bond claims have strict notice requirements and timeframes.

5. Pre-qualification and walking away (the most underused leverage)

The single strongest leverage you have is the right to refuse work from GCs with bad payment histories.

Build a database of every GC you've worked with:

• Average days from pay app submission to payment
• Frequency of pay app disputes
• Retainage release history
• Change order responsiveness

GCs who consistently pay over 60 days should be priced higher (or fired) — not subsidized with your working capital.

How the best subs play the game

They price for the cash hole

Working capital cost is real. Build it into your bids:

• 30-day GC payment cycle: add 1% to the bid
• 60-day GC payment cycle: add 2% to the bid
• 90-day GC payment cycle: add 3% to the bid
• Plus retainage cost: add 0.5-1% based on retainage percentage and expected hold period

For a $500K project with 60-day pay and 10% retainage, that's an additional $12-15K in your bid. Most subs leave this on the table.

They have an actual line of credit (not credit cards)

A bank line of credit at prime + 2-3% costs roughly 1/4 of credit card debt. For a $1-3M sub, a $200-500K line of credit is realistic and changes the math entirely.

The bank wants to see:

• 2-3 years of profitable financials
• Clean tax filings
• A real bookkeeper (this matters more than people realize)
• AR aging report
• Backlog by GC

If your financials don't support a bank line, this is the work to do — not chasing factoring or credit card limits.

They negotiate supplier terms aggressively

Established subs with payment history can usually get:

• Net-45 from net-30 (15-day improvement)
• Net-60 on key suppliers (30-day improvement)
• Volume discounts that effectively fund the float

A 30-day improvement in supplier terms with a $100K monthly material spend is $100K of permanent working capital improvement.

They invoice every legally permitted milestone

The default AIA cycle is monthly. Some contracts allow biweekly. Some allow milestone billing for substantial deliverables. Check your specific contracts and bill at the maximum frequency allowed.

They aggressively manage retainage

Retainage that ages 18+ months on completed projects is your money — and it's almost always recoverable with active follow-up. Run a quarterly retainage report. Send formal demand letters. Use lien rights if necessary.

For most subs, $50-200K of stale retainage is recoverable with focused effort. That's working capital you don't need to borrow.

They diversify across GCs

Concentration above 30% revenue from a single GC is dangerous. If they slow-pay, you're exposed.

Stable subs target 4-8 active GC relationships, with no single relationship above 25% of revenue.

What to do when a GC stops paying

Sometimes GCs run into their own cash problems and slow-pay or stop paying. The escalation:

1. Day 5 past due: Email demand citing prompt pay statute
2. Day 15 past due: Phone call to GC's project manager AND accounting
3. Day 30 past due: Formal letter from your office, certified mail
4. Day 45 past due: Notice of intent to lien
5. Day 60 past due: File mechanics lien (if within statutory window)
6. Day 90 past due: Engage construction attorney; consider bond claim if applicable

Each step costs more in relationship damage. But waiting too long forfeits your strongest leverage (lien rights expire). The right answer is usually to escalate faster than feels comfortable.

When the system doesn't work

Sometimes the system genuinely doesn't work — the GC is structurally broken, the project is failing, the owner has run out of money, or there's fraud.

Warning signs:

• GC asking you to "wait one more cycle" repeatedly
• Other subs talking about non-payment
• Project manager turnover
• Site visits showing slowed progress
• GC paying smaller invoices but slow-paying larger ones (cherry-picking)

When these signs appear, the answer is usually to file lien rights immediately and pursue collection aggressively, even if it ends the relationship.

When to call Level

For subcontractors at the $1-10M revenue level, fractional CFO work focuses on:

• 13-week cash forecasting that incorporates actual GC payment patterns
• Bank line of credit sourcing and structuring
• AR aging and retainage management discipline
• Bid pricing review to recover working capital cost
• Contract review for payment terms and lien rights preservation

Most small subs hit the cash crisis cliff somewhere between $1-3M revenue. The CFO support is what makes the difference between cycling through bankruptcies and scaling sustainably.

FAQ

Can I charge interest on late GC payments? Yes, in most states with statutory prompt pay laws. The interest rates are typically 1-1.5% per month. Whether to actually charge them depends on the relationship — but having the right is leverage.

What's the cost of a mechanics lien filing? $50-300 in filing fees depending on the county, plus attorney fees of $250-2,000 if you use a lien filing service or attorney. Specialized services (Levelset/Procore Pay) charge $200-500 per lien. The cost is small relative to the leverage.

How long should I wait before filing a lien? File preliminary notices immediately at project start (these don't damage relationships). Once payment is past due, follow your state's escalation timeline. Don't let lien rights lapse — once the statutory window closes, you've lost your strongest tool.

Should I work for GCs that don't have payment bonds? Bonded projects (mostly public) give you bond claim rights as backup. Unbonded projects rely entirely on lien rights and the GC's solvency. For unbonded private projects, do harder due diligence on the GC and the owner before accepting work.

Related reading:

• AIA Billing and the 25-Day Cash Hole
• How Retainage Kills Contractor Cash Flow
• Why Contractors Bill Millions and Collect Thousands Less