The Residential Job Is Financing the Commercial One

You poured a residential driveway on a Friday and had the homeowner's check before you loaded the trowels back on the truck. The same week you sent your third progress billing on a commercial parking structure, and you already know how that one goes. The general contractor's own people believe payment lands about 30 days after a pay application. The subs on that job know better. One widely cited survey found they wait an average of 56 days, and nearly two-thirds report being slow-paid. Pull back to the whole industry and construction runs roughly 83 days of average sales outstanding, among the highest of any sector in the country, according to CreditPulse's 2025 benchmarks.

Here is what that does to your books, whether or not anyone has said it out loud. The cash from your fast residential work is funding the crews, the fuel, and the material on your slow commercial work. The driveway that paid today is carrying the deck that pays in the spring. That arrangement holds for a while. It stops holding the moment residential volume softens or commercial backlog climbs, and in most markets those two move together.

The retainage nobody counts as margin

On top of slow pay, commercial owners hold back a piece of every progress payment until the job is done. Retainage usually runs 5 to 10 percent, though a growing list of states, California and New York among them, now cap it at five. On a two-million-dollar contract at 10 percent, that is $200,000 you do not see until substantial completion, and often only half of it then. The rest waits out the defect period.

For a lot of concrete contractors, that held-back slice is the profit on the job. You have already spent the labor and the material at a hundred cents on the dollar. You are collecting ninety, with the last ten hostage to a punch list and a closeout you do not control. Rabbet's 2025 payment report put a number on the whole mess, estimating that slow and inconsistent payment works like 15 percent tax on the industry, roughly $299 billion in a single year. Your share of that tax is real, and it is sitting in other people's bank accounts earning them interest.

You are the lender, and your rate is zero

Strip the language away and the residential side of your business is making an interest-free loan to the commercial side every week. The homeowner pays you now. The GC pays you in 2 months, minus a retention you chase for another six. The gap gets filled by whatever cash is on hand, which is the cash the driveways brought in.

The danger is that this feels like strength. Revenue is up, the phone rings, both books are busy. But growth on the commercial side eats working capital faster than the residential side can refill it, and the faster you grow the wider the hole gets. Plenty of concrete outfits have booked a record year and run out of money in the middle of it. Not because the work was unprofitable. Because the profit was locked in receivables and retainage while payroll came due every Friday in cash.

Stop letting one number hide two businesses

The fix starts with refusing to look at a single blended cash position. You have two businesses with two different collection clocks, and averaging them together hides the exact problem you need to see.

Separate them on paper. Track residential and commercial receivables on their own, and watch how many days each one actually takes to convert, not what the contract says. Then price the commercial work for the carry. If a job ties up your cash for ninety or 120 days, that cost belongs in the bid, the same as the concrete and the finishers. Contractors who never do this are, in effect, discounting their commercial work by the interest they are eating, and handing the difference to whoever holds the money longest.

Then fund the gap on purpose rather than by accident. A line sized to your commercial receivables, drawn against real billings, is cheaper and steadier than living off the residential float and praying the mix does not shift. The residential margin should be yours to keep, not the reserve that quietly bankrolls the slowest payer on your job list.

Run the number this month. Add up everything owed to you on commercial work, including retainage you have not chased. That figure is what your residential customers are financing for free. It is almost always larger than the owner expects, and it has been that size for a long time.