Construction is the most cash-flow-hostile business there is, because you pay for materials and labor weeks or months before the customer pays you, so staying alive depends less on being profitable and more on never running out of cash. The way you win is boring and reliable: take deposits, bill often, keep a real cash buffer, ring-fence the money that is not yours, get a line of credit before you need it, and stay on top of retainage. Most trade businesses that go under were busy the whole time, and plenty were profitable on paper. They just ran out of cash waiting to get paid. Profit is an opinion that shows up at year-end. Cash is the thing that makes payroll on Friday. Here is how to manage it.
Why the trades eat cash alive
Three features of construction combine to drain cash:
- You spend before you collect. Materials and labor go out the door at the start of a job, and payment comes at the end, or in stages, or 30 to 60 days after you invoice. On a big job that gap can be tens of thousands of dollars you are floating out of your own pocket.
- The work is lumpy and seasonal. Feast-or-famine is the norm. A run of good months followed by a dead stretch will bankrupt a business that scaled its spending to the good months.
- Money gets held back. Retainage means a slice of what you have earned, often 5 to 10 percent, sits unpaid until well after the job is done. Slow-paying customers and GCs stretch it further.
Understand that and you stop being surprised by cash crunches and start planning around them.
Keep a real buffer, and respect the 90-day rule
The single most protective habit is a cash cushion. Aim to build and hold at least three months of overhead in reserve, so a slow stretch or a slow-paying customer does not force you into a corner. Build that buffer before you leave a steady paycheck or take on your first large job, not after.
Then apply the 90-day survival rule: never start a job that will exhaust your working capital. If you cannot float the material cost for 30 days, you need a deposit structure that funds it or a materials credit account at your supply house, not a leap of faith that the customer pays fast. A single large job you cannot cash-flow can take down an otherwise healthy business.
Use the per-job levers (they live in their own guides)
Most of your cash-flow control happens at the job level, and each lever has its own detailed guide. The short version:
- Deposits fund materials before work starts, so you are not the bank. How much you can take is capped in some states, so see Deposits and progress billing.
- Progress billing turns finished work into cash on a regular cycle instead of one lump at the very end. Never let 60 days of work pile up unbilled.
- Invoicing fast and following up is what actually converts billed work into money in the account. See The invoice that gets paid.
- Retainage management means tracking every dollar held back and negotiating a step-down where you can. See Retainage and prompt pay.
- Supplier terms like Net-30 accounts give you 30 days of float on materials, and they build business credit at the same time (see Business banking and building credit). If a supplier offers an early-pay discount like 2/10 Net 30, taking it is worth roughly 36 percent annualized, so pay early when you have the cash.
This guide is the company-level view; those guides are the mechanics.
Ring-fence the money that is not yours
A big share of the cash flowing through your account was never yours to spend, and treating it like income is how businesses get blindsided:
- Tax money. Set aside a slice of every payment for income and self-employment tax so the quarterly bill does not gut you. How much, and how, is in How much to set aside for taxes.
- Sales or use tax on materials, where your state works that way (see Sales tax on construction).
- Payroll and its taxes, if you have staff. The taxes you withhold are the government's money, not float.
- Retainage, which is earned but not yet collected. Track it as the receivable it is, not as cash you have.
The simple discipline is to think of your account as holding several piles, only one of which is truly yours to live on. Move the tax reserve to a separate account if you are tempted to spend it.
Get a line of credit before you need it
A business line of credit is the shock absorber for the gap between working and collecting. The catch is that banks do not lend to businesses in trouble, so the time to set one up is while you still have steady income or regular work on the record, not the week you are short for payroll. Apply early, even if you do not draw on it, and use it responsibly when the timing gap hits. Building the business credit that gets you approved is covered in Business banking and building credit.
Survive the slow season on purpose
Feast-or-famine only sinks you if you spend like every month is a feast. In the busy stretch, deliberately bank a reserve for the lean one instead of scaling up your personal spending to match your best month. Line up a maintenance or smaller-job pipeline you can lean on when the big work dries up, and time big equipment purchases and tax moves for when cash is strong. Planning the year's rhythm, including the weather side of it, is covered in Working through the seasons.
Read your own cash position
You cannot manage what you do not look at. Keep a simple rolling view of what is coming in (invoices due, retainage releases) and what is going out (payroll, materials, rent, the tax reserve, loan payments) for the next several weeks. It does not need to be fancy; a spreadsheet or your accounting software's cash forecast is plenty (see Accounting software for contractors). The number to watch hardest is underbilling: work you have done but not yet invoiced. Underbilling is money you earned and are financing for free, and it is the quiet early warning that a cash crunch is coming.
Common questions
How much cash buffer should a contractor keep?
Aim for at least three months of overhead held in reserve. Overhead is your fixed monthly cost of being in business, so three months of it is enough to ride out a slow stretch or a slow-paying customer without being forced into a bad decision. Build that cushion before you leave a steady income or take on your first large job, because construction's spend-before-you-collect timing means cash gaps are a matter of when, not if. Keep the reserve, plus your tax set-aside, in a separate account so it does not get spent as if it were profit.
Why am I broke if my jobs are actually profitable?
Because profit and cash are not the same thing, and construction times them badly. You spend on materials and labor at the start of a job and collect at the end or weeks after invoicing, so a profitable business can still be short of cash at any given moment, especially while retainage is held back and slow payers drag out. The fix is cash management, not more work: take deposits, bill progress often, chase invoices, track retainage as the receivable it is, and hold a buffer. Watch for underbilling, work done but not yet invoiced, which quietly ties up your cash.
Should I get a business line of credit?
Yes, and set it up before you need it. A line of credit covers the gap between paying for a job and collecting on it, which is the exact pinch that breaks small contractors. The problem is that banks will not lend to a business already in distress, so you apply while you still have steady income or regular work on record, even if you do not draw on it yet. Build the business credit that gets you approved through Net-30 vendor accounts and consistent, on-time payments, covered in Business banking and building credit. Draw on the line responsibly, for timing gaps, not to cover losses.
How do I get through the slow season without going under?
Bank a reserve during the busy months instead of scaling your spending up to match them. Feast-or-famine only sinks businesses that treat their best month as normal. In the good stretch, set aside a cushion for the lean one, keep your personal draw steady rather than spiking it, and line up smaller or maintenance work you can fall back on when the big jobs dry up. A cash buffer of a few months of overhead plus a line of credit set up in advance turns the slow season from a crisis into a planned dip.
What is the fastest way to improve my cash flow?
Bill more often and follow up faster, and take a deposit before you buy materials. Most cash-flow pain is self-inflicted timing: work sits unbilled, invoices sit unchased, and you finance materials out of pocket. Shorten every one of those gaps. Invoice the day a milestone is done, follow up the moment an invoice goes late, and structure deposits and progress payments so the customer's money funds the work instead of yours. The per-job mechanics are in Deposits and progress billing and The invoice that gets paid. These cost nothing and work immediately.
The honest bit
- Nothing here is a state number, but the levers that touch state law are: how much deposit you can take, retainage caps and release timing, and prompt-pay deadlines all vary by state and are covered in the payment-and-money guides and Working in Your State. Do not assume another state's caps are yours.
- The three-month buffer and the 90-day rule are planning heuristics, not guarantees. A very seasonal or very large-job business may need more.
- This is general guidance, not financial advice. If the business is already in a cash crisis, talk to your CPA and your bank early; the worst time to seek help is the week you cannot make payroll.
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