Subcontractor business

How to run a profitable subcontracting business

Profitable subcontractors know their true labor cost, recover overhead in every bid, pick general contractors who pay, track production weekly, and collect every dollar of change orders and retainage.

An office manager and contractor review invoices with a calculator and laptop in a construction office.
Review invoices, committed costs, and cash timing together before making project decisions. AI-generated illustration.

A subcontracting business is profitable when five things are true: you know your fully burdened labor cost, every bid recovers overhead plus a real profit, you work for general contractors who pay on time and treat changes fairly, you compare actual hours to estimated hours every week, and you bill and collect every change order and every dollar of retainage. Most trade subs who stay busy but broke are missing two or three of those, not all five.

Subs carry a lopsided share of risk. You fund labor and material weeks before the GC pays, you live with pay-when-paid clauses, and you absorb back charges for problems you did not always cause. The margin has to be built on purpose.

The five profit levers for a subcontractor

1. Know your true labor cost

A $32 an hour wage is not a $32 cost. Add the employer's payroll taxes, workers' compensation, general liability that rates on payroll, health and retirement contributions, paid time off, and the hours you pay for but cannot bill, like shop time and drive time. The federal pieces are fixed by law: the IRS lists the employer share of Social Security at 6.2 percent and Medicare at 1.45 percent, and FUTA at 6.0 percent on the first $7,000 of each employee's wages, which drops to 0.6 percent after the maximum 5.4 percent credit for employers who qualify. State unemployment and workers' comp rates vary by state and by your claims history. How to calculate labor burden walks through it.

2. Recover overhead in every bid

Add up a year of costs that do not belong to a single job: office rent, office staff, estimator, owner's salary, trucks not charged to jobs, software, insurance not rated on payroll, accounting, and bonding. Divide by expected field labor hours or direct cost to get a rate. Then put it in every bid. See how to calculate construction overhead rate.

3. Choose your general contractors

Not all revenue is equal. Rank each GC you work for on days to pay, how they handle change orders, back charge history, retainage release, and how ready the site is when you show up. A GC who pays in 75 days and fights every change may be costing you money even at a good contract price. Spend estimating time on the ones who score well. How to build relationships with general contractors covers the other side.

4. Track production weekly

Break each job into a few measurable units: square feet hung, linear feet of pipe, fixtures set, devices trimmed. Each week, compare installed quantity and hours spent to the estimate. If a crew estimated at 40 boards per day is hanging 30, you find out in week one, not at the end of the job. Labor productivity is where trade margins are won or lost.

5. Bill everything and collect it

Price changes before doing them, bill them on the next pay application, and chase retainage the day your scope is accepted. Unbilled change work and forgotten retainage are pure profit left on the table. See how subcontractors should track change orders and how to manage retainage as a subcontractor.

Worked example: a drywall sub that looked busy but was not making money

Say a drywall and framing sub does $3.2 million a year with 22 field workers. The owner bids at labor wage plus material plus 15 percent. At year end, the books show only a thin net profit.

Example: where the money went
ItemAnnual amountNote
Revenue$3,200,000Contract billings
Field wages$1,280,000Bid at wage only
Labor burden not in bids$420,000Taxes, comp, benefits, PTO, unbillable hours
Materials$900,000Bid at cost plus markup
Overhead$480,000Office, owner, trucks, insurance
Unbilled change work (estimated)$70,000Revenue never collected, not in the lines above
Net before tax$120,0003.75 percent

The fix in this example is not more work. The owner rebuilds the labor rate with burden included, adds an overhead rate, and requires a signed change order or written directive before extra work. The company drops one GC with 90 day pay and heavy back charges. Revenue the next year is $2.9 million, but each bid now carries its burden and overhead, and changes get billed. The mix of lower volume, full cost recovery, and billed changes is what moves the margin.

Cash flow is part of profitability

A profitable sub can still run out of cash. Payroll goes out weekly; GC payments come monthly or slower, less retainage. Build a 13 week cash forecast, bill on the GC's cutoff date every month, and keep a line of credit open before you need it. For public jobs you may also need bonding. The U.S. Small Business Administration's surety bond guarantee program helps small contractors get bonds, and its page lists contracts up to $9 million for non-federal work and up to $14 million for federal work, with a fee of 0.6 percent of the contract price on performance and payment bond guarantees. Read how to manage cash flow as a subcontractor.

Read the subcontract before you price it

Contract terms move profit as much as unit prices do. Before you sign, check the retainage rate and release trigger, the payment clause (pay-if-paid vs pay-when-paid), back charge notice rules, how changes must be requested, the insurance limits you must carry, and any flow-down clause that drags the prime contract onto you. A clause that holds 10 percent until the whole building closes out, on a job where your scope ends in month four, is a financing cost you should price or negotiate. How to read a general contractor subcontract walks through the clauses that matter most.

Keep a one page list of terms you will not accept and terms you will accept only at a higher price. Your estimator should check every subcontract against it before the bid is final, not after the award.

Mistakes to avoid

  1. Bidding at wage rate instead of burdened labor cost.
  2. Treating overhead as something profit will cover.
  3. Confusing markup with margin. A 15 percent markup is about a 13 percent margin. See markup vs margin in construction.
  4. Doing extra work on verbal direction and hoping to bill it later.
  5. Accepting any GC's work because the schedule has a gap.
  6. Waiting until job end to learn whether a job made money.

Templates, terms, and tools

Use the job cost report template, the construction timesheet template, and the construction cash flow template. Related reading: how to price work as a subcontractor, how to handle back charges from general contractors, and how to run a weekly job cost review.

Smart Business Automator shows estimated vs actual cost on every job, tracks change orders and retainage per contract, and flags jobs where hours are running ahead of progress. See job costing and WIP automation.

Frequently asked questions

What profit margin should a subcontractor aim for?

It depends on trade, size, and risk, and reliable figures vary by source. Set your target from your own overhead and the return you need, and check it against your job cost history rather than a rule of thumb.

Why are busy subcontractors often short on cash?

They pay labor weekly and get paid monthly or slower, less retainage, while unbilled change work and slow-paying GCs stretch the gap. More volume can make the cash gap worse.

How do I know which general contractors are worth working for?

Track days to pay, change order approval, back charges, retainage release, and site readiness for each GC. The numbers usually point to one or two that cost more than they pay.

What is included in labor burden?

Employer payroll taxes, workers' compensation, payroll-rated insurance, benefits, paid time off, and unbillable hours. Federal tax rates are set by the IRS; state rates and insurance vary.

Sources

  1. IRS: Topic no. 751, Social Security and Medicare withholding rates
  2. IRS: Topic no. 759, Form 940, Employer's Annual Federal Unemployment (FUTA) Tax Return
  3. U.S. Small Business Administration: Surety bonds
Written and edited by

Maurice Francois writes and edits construction operations guides for Smart Business Automator. More from Maurice on the Scaling Legends podcast.

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