Per Diem Construction Jobs: The Tax-Free Rules Explained

Per diem is the daily allowance paid to a worker who is traveling for the job and is not at home. It is meant to cover lodging, meals, and incidental expenses. Done right, per diem is one of the most powerful wealth-building tools in the building trades — a tax-free supplement that can add $20,000-$40,000 a year to a traveling brother's pocket without the IRS taking a cut. Done wrong, it costs you thousands. This chapter walks you through both.

THE TWO BUCKETS — LODGING AND M&IE

Per diem is split into two categories that work very differently:

Lodging (hotel, rental, RV park) — paid as actuals up to a cap. If your hotel costs $98 and the federal cap for that city is $110, you get reimbursed $98. If the room is $115, you eat the $5 over. Save every hotel receipt.

Meals & Incidental Expenses (M&IE) — paid as a flat daily allowance, no receipts required. Whether you eat at a steakhouse or pack a sandwich from the cooler, you get the same dollar amount. What you don't spend is yours to keep.

THE 2026 FEDERAL NUMBERS

The General Services Administration (GSA) sets per diem rates for the federal fiscal year. FY 2026 (October 1, 2025 through September 30, 2026) rates are unchanged from FY 2025: Standard CONUS rate: $178 per day ($110 lodging + $68 M&IE) Non-Standard Areas (NSAs): 296 cities with higher rates High-cost cities (NYC, San Francisco, certain Alaska sites): can reach $375-$391/day Travel day rule: First and last day = 75% of M&IE only ($51 standard) Incidentals-only rate: $5/day if you're not staying overnight Look up the rate for your job location at gsa.gov/travel/plan-book/per-diem-rates. The rate is determined by the location of the work activity, not where you sleep.

THE IRS HIGH-LOW METHOD

Some contractors use the IRS "high-low" substantiation method instead of city-by-city rates. For 2026:

High-cost areas: $319/day ($86 M&IE) All other localities: $225/day ($74 M&IE) If your contract says "high-low," that's what they're referring to.

TAX-FREE — UP TO FEDERAL LIMITS

This is the magic. Per diem at or below the federal rate is tax-free. It doesn't appear on your W-2. The IRS doesn't consider it income. You don't pay federal tax, state tax, FICA, or Medicare on it. Anything paid above the federal rate is taxable. If GSA says $178 and your contractor pays $250, the extra $72 gets taxed like wages.

This is why a brother on a refinery turnaround at $52/hour with $200/day per diem can take home more than a brother at $65/hour on a local job. The hourly wage gets taxed at 25-30% federal plus state plus FICA. The per diem comes home whole.

Do the math before you turn down travel work.

WHO QUALIFIES — THE TAX HOME RULE

Per diem is tax-free only when you have a permanent tax home that you're traveling away from. A tax home is where you regularly conduct business and incur ongoing living expenses — typically the place where you maintain your primary residence, pay rent or a mortgage, and where your driver's license is registered.

If you don't have a permanent tax home, the IRS classifies you as an "itinerant worker" — and your entire per diem becomes taxable wages. Boilermakers, traveling pipefitters, and ironworkers who jump from job site to job site without a real home base are the most common victims. To establish and protect your tax home: Maintain a permanent residence you return to between jobs Pay rent or a mortgage on that residence Have utilities, mail, and a driver's license at that address Keep voter registration there Spend time there between jobs If you live in a hotel year-round chasing work, the IRS may decide you don't have a tax home — and tax your per diem retroactively.

THE 1-YEAR RULE — THE BIGGEST TRAP

An assignment expected to last more than one year is no longer "temporary" in the eyes of the IRS. Per diem for that job becomes fully taxable.

This catches brothers on long shutdowns, nuclear refueling, big LNG builds, and semiconductor fab construction. The trap:

Month 1-11: per diem is tax-free Month 12 forward: per diem becomes taxable If you KNOW from day one the job will last 14 months, the entire per diem from day one is taxable retroactively What to do: Know the expected duration of your assignment before you accept. Read your dispatch slip. Ask the steward. If the job is planned for over a year, factor that into your hourly negotiations.

HOW BROTHERS GET BURNED — REAL SCENARIOS

Scenario 1: No tax home, no per diem. A young boilermaker travels for three years straight, sleeps in hotels and RV parks, has his mom's address on his license. IRS audits him. He owes back taxes on three years of per diem because he never had a real tax home.

Scenario 2: Contractor pays below GSA rate. You get $90/day total when GSA says $178 for that city. Legally allowed — but you're leaving $88/day on the table for no reason. Ask the steward if the contract specifies GSA rates or a flat rate.

Scenario 3: Per diem clawback when you quit early. You take the job, get per diem advanced as a lump sum, then walk after 4 weeks. The contractor claws back the unused per diem from your final check. Read the dispatch slip for clawback language before you accept.

Scenario 4: Job extends past a year, taxes hit retroactively. You signed up for an 11-month turnaround. It extends to 14 months. The IRS reclassifies your per diem as taxable from day one. You owe thousands in back taxes.

Scenario 5: No documentation, no proof. You worked 90 days in Texas on a turnaround. IRS audits. You can't produce dispatch slips, hotel receipts, mileage logs, or a work calendar. They tax the whole per diem as income.

WHAT TO DO — EVERY TRAVEL JOB

Before you accept: Look up the GSA rate for the job location at gsa.gov Ask the dispatcher: "Is per diem at GSA rate or flat?" Ask: "What's the expected duration?" (Watch the 1-year line) Read the dispatch slip for clawback or early-quit language Confirm your tax home is documented (utility bills, lease, mortgage statements) On the job: Save every hotel receipt Keep a written daily log: dates worked, location, employer Save dispatch slips and project agreements Photograph or scan all paperwork to cloud storage Note any per diem on your paystub — taxable vs. non-taxable At tax time: Bring all per diem documentation to a CPA who knows the trades Don't use TurboTax for a complicated traveling year Ask the CPA about Schedule C deductions if you're a 1099 contractor Verify all per diem amounts match GSA limits for that city/date

WHEN TO FIGHT FOR IT — AND WHEN TO WALK AWAY

Some contractors lowball per diem hoping workers won't notice. You notice. If the contract is silent on rates and the contractor is paying half of GSA, call your business agent. Per diem is often negotiated into the Project Labor Agreement (PLA) or Collective Bargaining Agreement — and the contractor may be in violation.

If the per diem is set by the PLA and it's just a low PLA, you have a different fight — that's a contract renegotiation issue.

When to walk: A job paying $42/hour at GSA per diem is often better than $52/hour at half GSA. Do the math. The tax-free portion matters.

ONE LAST THING

Per diem is one of the most powerful wealth-building tools the trades offer. A brother who travels six months a year, takes the per diem clean, banks the difference between his daily allowance and his actual spending, can build a six-figure cushion in a decade that a local journeyman will never match.

The brothers who built generational wealth in the boilermaker locals, the pipefitter halls, the boomer trades — they did it on per diem more than they did it on hourly scale. Read the dispatch slip. Save the receipts. Document your tax home. Talk to the steward when something looks wrong. And find a CPA who actually understands traveler taxes. Your future self will thank you.

Per diem rates and tax treatment vary by employer, contract, year, and IRS rules. Verify current GSA rates at gsa.gov and consult a CPA familiar with union and traveler taxes for your specific situation.