Change orders and contracts

Time and materials contracts: when to use them

Use time and materials when you cannot define the scope well enough to give a fixed price: service calls, emergency repairs, investigative work, and small changes where the unknowns are real. Protect both sides with set hourly rates, a material markup, a not-to-exceed number, and daily tickets.

A contractor and plan reviewer discuss drawings and permit paperwork across an office desk.
Keep plans, permit requirements and approvals together when preparing construction work. AI-generated illustration.

A time and materials contract pays the contractor fixed hourly rates for labor and equipment, plus the cost of materials with an agreed markup. It makes sense when nobody can describe the work well enough to price it: opening a wall to trace a leak, emergency storm repair, demolition with unknown conditions behind it, or a run of small owner requests on a building you service. It is a poor fit when the scope is clear, because the owner carries the risk of inefficiency and will watch every hour you bill.

Even the federal government treats T&M as a last resort. FAR 16.601 allows it only when it is not possible at the time of contracting to estimate the extent or duration of the work, or to anticipate costs with any reasonable degree of confidence. It also requires a ceiling price the contractor exceeds at its own risk. Private owners are not bound by the FAR, but that logic is a good test for any job.

When a T&M contract makes sense

  • Unknown conditions. Selective demo, water damage, or structural repairs where the extent is unknown until you open it up.
  • Emergency work. A burst pipe or storm damage where waiting for a priced proposal costs the owner more than the premium.
  • Service and maintenance. Ongoing small calls for a facility where pricing each one would cost more than doing it.
  • Change work under a fixed contract. Changes that cannot be priced in advance, often called T&M tickets or force account work.
  • Design still moving. Early work on a job where drawings are not ready, as a bridge to a lump sum or cost-plus agreement.

When T&M is the wrong choice

If you could give a fixed price with a reasonable contingency, do it. Owners often push back on open-ended billing, and every daily ticket becomes a chance to argue. A fixed price also rewards an efficient crew. On T&M, a crew that finishes early earns you less.

T&M compared to other contract types
Contract typeWho carries cost riskBest for
Time and materialsMostly the owner, up to any capUnknown scope, emergency and service work
Cost-plus feeOwner, with open booksLarger jobs with evolving design
Fixed price / lump sumContractorClear drawings and specs
Unit priceShared: contractor on unit cost, owner on quantityRepetitive work with uncertain quantities

How to set up a T&M contract in 6 steps

  1. Build loaded labor rates. Start from wages, add labor burden (payroll taxes, insurance, benefits), then overhead and profit. Publish a rate per classification: foreman, journeyman, apprentice, laborer. Set separate overtime and weekend rates.
  2. Set equipment rates. List owned equipment at hourly or daily rates and say that rented equipment bills at invoice cost plus markup.
  3. State the material markup. Material at invoice cost plus a stated percentage, with small tools and consumables either included in labor rates or billed as a percentage. Pick one and write it down.
  4. Add a not-to-exceed number. A cap gives the owner comfort and forces a conversation before you blow past it. Require written approval to raise it.
  5. Define documentation. Daily T&M tickets with names, classifications, hours, equipment, and materials, signed by the owner's representative the same day.
  6. Agree on billing terms. Weekly or biweekly invoices with tickets and supplier invoices attached, and payment terms to match.

Worked example: a water damage repair

Say a contractor is called to a medical office after a supply line failed above the ceiling. Nobody knows how far the water traveled. The contractor proposes T&M with a not-to-exceed of $25,000, and the owner signs. The rate sheet is illustrative.

Example week-one T&M invoice
LineQuantityRateAmount
Foreman32 hours$95/hr$3,040
Carpenters (2)64 hours$78/hr$4,992
Laborer40 hours$58/hr$2,320
Dehumidifier rentalInvoice $640Cost + 15%$736
Drywall, insulation, ceiling tileInvoices $2,180Cost + 15%$2,507
Total week one$13,595

By midweek two, the crew finds wet framing in a second exam room. The running total is projected to reach $23,000 before the second room is done. The PM sends the owner a written notice that the cap will be exceeded, with photos and a revised estimate of $31,000. The owner approves the new cap before the crew opens the second room. That one email avoids the classic T&M dispute: an owner who receives a bill 25 percent over the number they thought was firm.

How to run T&M work in the field

A T&M contract is only as good as the paperwork behind it. The office can write perfect rates, but if the foreman fills out tickets on Friday from memory, the owner will cut hours and you will have nothing to argue with.

  1. One ticket per day, per crew. Write it before the crew leaves the site. Include start and stop times, who worked, their classification, and a short description of the work by room or area.
  2. Get the signature the same day. The owner's rep signs for hours and quantities, not for the rates. Rates come from the contract. If nobody is on site to sign, email a photo of the ticket that evening and ask for a reply.
  3. Attach material receipts quickly. Snap the supplier ticket when it arrives. Waiting for the monthly statement makes it hard to tie materials to the right job and day.
  4. Compare the running total to the cap every week. The PM should know the projected final cost, not just the billed to date. Warn the owner in writing well before the cap is reached.
  5. Close the work out cleanly. When the scope becomes clear, offer to convert the rest to a fixed price. Many owners welcome it, and it rewards your crew for working efficiently.

T&M mistakes to avoid

  • Unsigned tickets. If the owner's rep did not sign it that day, expect to argue about it later.
  • Rates that leave out burden or overhead, so the job looks profitable and is not.
  • Blowing through the not-to-exceed without written approval.
  • Vague descriptions like "misc. work." Write what was done and where.
  • Mixing T&M and contract work on the same timecards. Use separate cost codes so hours land in the right bucket.
  • Billing monthly when tickets pile up. Weekly billing keeps disputes small.

Templates and tools for T&M work

The construction timesheet template and the construction invoice template cover the paperwork. For the field side, read how to track time and materials work accurately. If the T&M work is a change on a fixed-price job, follow how to price a change order and log it with your other changes.

Smart Business Automator captures T&M hours and material costs by job and cost code, builds the invoice from approved tickets, and shows the running total against the not-to-exceed in the job costing view. See job costing and WIP automation.

Frequently asked questions

What is a not-to-exceed in a T&M contract?

It is a cap on the total the owner will pay without further approval. The contractor bills actual time and materials up to that amount. Going over requires written agreement to raise the cap. On federal T&M contracts, FAR 16.601 requires a ceiling price the contractor exceeds at its own risk.

What markup is normal on materials in a T&M contract?

There is no single standard. The percentage is set by the contract, and it varies by trade, region, and job size. State it in writing before work starts, along with how small tools, consumables, and rented equipment are billed.

Is a T&M contract the same as cost-plus?

They are related but not the same. In T&M, labor is billed at fixed hourly rates that already include overhead and profit. In cost-plus, the contractor bills actual costs, including real payroll cost, plus a separate fee or percentage.

Do owners have to sign T&M tickets?

Only if the contract requires it, but you should insist. A signed daily ticket is the best evidence that the hours and materials were real and approved.

Sources

  1. Acquisition.gov: FAR 16.601, Time-and-materials contracts
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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