"The P&L says we made $400K last year. So why am I sweating payroll this Friday?" If you've ever asked that question, this guide is for you.
In most industries, profit and cash travel together — you sell something, you get paid, the money shows up. Construction is different. You spend money for weeks before you're allowed to ask for any, you get paid on someone else's schedule, and a slice of every invoice is held hostage until long after the work is done.
That means a construction P&L can be completely accurate and completely misleading at the same time. The profit is real — it's just not in your bank account yet, and it may not arrive for months. Meanwhile payroll is due Friday, every Friday.
Work completed but not invoiced is money you've spent that nobody owes you yet — on paper. Slow pay apps, unapproved change orders, and missed draws leave earned revenue stranded in the ground. Full guide: over- vs. under-billing.
Front-loaded billings put cash in your account that belongs to unfinished work. It looks like winnings, so it gets spent — then the back end of the job arrives, costs keep coming, and there's nothing left to bill against them.
If you do $10M of retainage-bearing work at 10%, roughly a million dollars of your money is sitting in other people's bank accounts at any given time — often until well after final completion. Retainage is usually most or all of your profit margin, held until last.
Payroll is weekly. Suppliers are net-30. Your pay app is monthly, approved in 2–4 weeks, and paid on net-30/45 after that — sometimes only when the GC gets paid. You're covering 6–10 weeks of costs on every job, all the time, from your own pocket.
Every new job demands mobilization, labor, and materials weeks before its first draw arrives. Grow 30% and you're financing 30% more work-in-progress with the same bank account. This is why contractors so often hit a cash crisis in their best year ever.
Owner draws sized on "we made $400K," new equipment bought against paper profit, and then the tax bill on income you haven't collected yet. If distributions follow the P&L instead of the cash position, the business slowly bleeds out from the top.
Take a healthy, profitable job: $600,000 contract, $480,000 cost, 20% margin, 10% retainage, four months of work, customer pays 45 days after each monthly invoice. Here's your cumulative cash position:
| Month | Costs Out (cum.) | Cash In (cum.) | Your Position |
|---|---|---|---|
| Month 1 | $120,000 | $0 | –$120,000 |
| Month 2 | $240,000 | $0 | –$240,000 |
| Month 3 | $360,000 | $135,000 | –$225,000 |
| Month 4 | $480,000 | $270,000 | –$210,000 |
| Month 5 | $480,000 | $405,000 | –$75,000 |
| Month 6 | $480,000 | $540,000 | +$60,000 |
| Retainage release | $480,000 | $600,000 | +$120,000 ✓ |
Assumes monthly billing of $150,000 received at 90% (10% retainage) 45 days later. Retainage often releases months after completion.
Read that middle column again: to earn $120,000 of profit, you had to float up to $240,000 of your own cash — for months. Now run five of those jobs at once, add a slow-paying GC, and grow the backlog 30%. The P&L says you're thriving. The bank account is a war zone.
Blackline Finish-tier clients get a 13-week cash flow forecast, monthly WIP schedule, and a CFO who reads them with you — so the crunch shows up on paper, not at payroll.
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