8 types of construction contracts: A practical guide

A construction contract sets the financial and legal terms of the job: how the work is scoped, how contractors get paid, and who absorbs the cost when something changes. A good contract outlines factors like project scope and cost clearly, keeping costs in check. On the other hand, a poorly structured contract can lead to change orders and late payments, which quickly erodes profit margins.

Understanding the different types of construction contracts can help contractors limit material and labor cost risks, protect payment rights, and establish clear policies for scope changes.

This guide is designed to help growing contractors understand the essential components of a construction contract, the common types, and how to choose the right one.

What is a construction contract?

A construction contract is a legally binding document outlining an agreement between two or more parties, typically the project owner and contractor or subcontractor. Contracts in construction define the scope, schedule, and price of the work, and they allocate risk between the parties before the work starts. Once a project is underway, both parties can refer back to the contract if and when disputes arise over scope, change orders, schedule slippage, or payment.

What are the key elements of a construction contract?

Though the language and structure may differ, there are several core components that are virtually always included:

• Scope of work defines contractor responsibilities, including what is and isn’t included, to prevent misalignment and avoid unpaid labor and profit loss.
• Project timelines outline start and completion dates and sequences, which helps prevent delays.
• Payment terms cover how much clients pay contractors, when contractors submit invoices, and how long owners have to complete payments.
• Schedules and milestones set timelines for each task’s completion and act as payment triggers, prompting invoices at certain progress points.
• Change order definitions detail in writing how scope changes are documented, priced, and approved before crews perform additional work.
• Termination clauses define when and how parties may end a contract, including payment terms for partially completed work.
• Warranties, liabilities, and indemnifications explain who takes responsibility for financial loss resulting from defective work, jobsite safety incidents, or third-party claims.
• Dispute resolution methods create a framework for resolving disagreements. They outline the escalation path, usually from mediation to arbitration to litigation.

8 key construction contract types

Choosing the right construction contract depends on individual project scope and the goals and risk tolerance of the parties involved.

Below are the most common examples of construction contracts with notes on when each one fits.

1. Lump sum contracts

With a lump sum contract, the contractor receives a fixed dollar amount in exchange for completing the project. This contract type fits straightforward projects with clearly defined scopes. 

However, if the project’s needs change, the contractor takes on the cost of overruns, which can hurt margins. Accurate estimates prevent this, so contractors need to reference historical job costing data before submitting bids.

2. Time and materials (T&M) contracts

For T&M contracts, the owner pays the contractor based on actual hours worked and materials purchased for a project. They’re typically billed on a regular cycle (e.g., weekly or monthly) based on submitted timesheets, signed daily logs, and material receipts. T&M contracts are often used for projects with unclear or shifting scope requirements.

Thorough documentation is necessary to prevent disputes and justify charges, so contractors need to maintain accurate time tracking and expense records throughout the job.

3. Unit price contracts

Unit price contracts outline a fixed price per unit of work. A unit is a smaller, measurable, and recurring component of a larger project, such as a square yard of asphalt or a cubic yard of poured concrete. Total price is determined by the number of units delivered. This agreement type is helpful for jobs with unclear total quantities of repetitive work.

4. Guaranteed maximum price (GMP) contracts

GMP contracts establish a capped amount that an owner will pay. Once the project is completed, the owner reimburses the contractor up to the GMP. In general, if the total project cost is lower than the GMP, both parties share the savings, while the working contractor covers expenses that exceed the GMP.

While GMP contracts keep expectations clear, the contractor absorbs overruns out of their fee or margin, which makes accurate construction bidding and ongoing cost control essential.

5. Cost-plus contracts

Under a cost-plus contract, the owner reimburses the contractor for project costs and pays an additional fixed or percentage-based fee. Contractors carry less risk with these contracts, as the additional fee acts as a profit-margin buffer.

Without a fixed total price, owners may be more likely to question charges and expenses, so a lack of transparency or poor job costing can result in disputes that damage contractor reputation or end in litigation.

6. Design-build contracts

Design-build contracts require one party (usually the contractor) to assume responsibility and liability for both the design and construction process. While this means the contractor takes on more risk, it also gives them greater control and flexibility over cost decisions and scheduling, often allowing firms to deliver projects more quickly.

7. Incentive/performance-based contracts

This contract type establishes a fixed total price, but it also outlines additional compensation when contractors exceed projected outcomes, like delivering a project early or staying under budget. Incentive-based contracts are often confused with GMP, but they’re not the same. GMP caps risk for the owner, while incentive contracts reward contractors for exceeding targets.

Contractors stand to benefit from incentive contracts, but only if they deliver projects early or under budget. So, tight project controls, clear schedule tracking, and disciplined cost forecasting can make or break this type of agreement.

8. Integrated project delivery (IPD) contracts

IPD contracts have a multi-party structure where the owner, architect, and general contractor share risks and rewards. This can reduce disputes, increase collaboration, and create shared accountability. But pre-contract negotiations frequently get complex, which may delay project start. 

Note that these contract types are rare and often only apply to complex, large-scale commercial projects. Even when contractors opt for IPDs, subcontractors and specialty trades typically still sign their own contracts with the GC.

Best practices for managing contracts in construction

The right contract type is only the start. To avoid disputes and protect margins, contractors need a few habits in place once the work begins.

Document scope changes in real time. 

Any undocumented or unapproved change can lead to a dispute that can harm relationships and revenue. Always include written change order approval requirements, and document scope changes the day they happen. The biggest source of disputes is crews following verbal instructions from an owner, PM, or superintendent without logging them as a change order or T&M ticket.

Align your contract type with how you track costs.

Your cost-tracking systems should always align with contract type. For example, lump sum contracts rely on accurate forecasting and estimates, while T&M contracts are more closely tied to detailed daily reports and cost logs.

Know your payment trigger conditions. 

Before submitting or paying invoices, look closely at the contract type and terms. Different contract types trigger payments in different ways. For example, cost-plus jobs require open-book backup, which means documenting receipts, timesheets and paid subcontractor invoices and including them on every invoice. And lump-sum job payments are tied to milestone completion and are typically billed using AIA G702/G703 pay applications.

Review clauses before execution.

Clauses outline liabilities for jobsite safety incidents, substandard work, and third-party claims. Don’t wait for an incident. Always review liability and indemnification clauses before signing a contract, not after the project gets underway.

Which contract is right for your job?

The right contract type depends on the project’s scope, the owner’s priorities, and how much risk the contractor is willing to absorb. Here’s a simple breakdown of how those factors map to each contract type:

Simplify construction operations with Miter

Contract type has a big impact on how contractors deliver work, who takes on risk, and how disputes are handled. But regardless of contract structure, firms need clear systems to track costs and maintain visibility.

With Miter Job Costing and Time Tracking, construction companies can capture fully burdened labor costs with real-time field data. The platform ties every hour to the right job and cost code in real time, and produces the documentation contractors need to back up billing on any contract type: job costing reports with fully burdened costs, certified payroll for prevailing wage work, and timesheet-level audit trails for T&M and cost-plus invoices.