The Most Common Construction Contract Types

Key takeaways:

• Select contract types based on scope clarity—use lump sum for well-defined projects with minimal expected changes, guaranteed maximum price or cost-plus when scope is evolving, and time and materials only when scope cannot be reasonably estimated upfront.
• Define change order procedures before signing by specifying approval authority, required documentation, and how modifications affect price and schedule, since construction projects almost always require mid-build changes.
• Add not-to-exceed clauses to time and materials contracts whenever you need scope flexibility but must maintain a hard budget ceiling to prevent open-ended spending.
• Track post-signature obligations including payment milestones, change order approvals, insurance expirations, and notice deadlines to avoid disputes and the 11% average contract value loss organizations experience after signature.

What is a construction contract?

A construction contract is a legally binding agreement between a property owner and a contractor that defines what gets built, how much it costs, and who’s responsible when things change. With U.S. construction spending at $2.19 trillion annually, the type of contract you choose determines how the contractor gets paid and who absorbs the financial hit if costs run over budget.

That matters more than you might think. According to research cited in the 2026 Contracting Benchmark Report, organizations lose an average of 11% of contract value after signature through issues like misaligned risk and poor lifecycle management. Pick the wrong contract structure for your project, and you’re either overpaying for certainty you didn’t need or exposed to cost overruns you didn’t plan for.

Every construction contract, regardless of type, covers the same four areas:

• Scope of work: What gets built, to what specifications, and by when
• Payment terms: How, when, and under what conditions the contractor gets paid
• Risk allocation: Who absorbs cost overruns, delays, and unforeseen site conditions
• Change management: How modifications to the original scope get handled and priced

Common elements of a construction contract

Before we get into the specific contract types, it’s worth knowing the standard clauses you’ll find in virtually every construction agreement. These show up whether you’re dealing with a small renovation or a large commercial construction project.

Plans and specifications are the drawings and technical documents that define what’s being built. General conditions set the ground rules—insurance, safety, how disputes get handled. Your payment schedule spells out when progress payments get released and how retainage (money held back until the project is complete) works.

Change order provisions matter more than most people realize. Construction projects almost always change mid-build, and this clause defines how those changes get requested, priced, and approved. Without a clear process here, you’re setting yourself up for arguments and delays later, contributing to lengthy cycle times—which average 58 days for construction and engineering contracts, according to the report.

You’ll also see clauses for indemnification, insurance requirements, liquidated damages (pre-agreed penalties for missing deadlines), termination conditions, and dispute resolution. How all these pieces interact depends on which contract type you’re working with.

Types of construction contracts

Here’s the thing about construction contracts—the type you choose shapes who carries the cost risk and how much room you have when the scope changes. Most projects use one of the seven structures below, though it’s common to see hybrids in practice.

Lump sum contract

A lump sum contract sets one fixed price for the entire project. The contractor agrees to deliver everything described in the scope for that number. If actual costs come in lower, the contractor pockets the difference. If costs run over, the contractor eats the loss.

This is the most common contract type in construction, and it works well when you have complete drawings, a detailed scope, and minimal expected changes—effectively shifting contractual risk to the contractor. The trade-off is that contractors know they’re taking on risk, so they bake contingencies into their bid. You get price certainty, but you may pay more upfront for it.

Payments typically happen on a milestone schedule or as a percentage of completion. And since the contractor’s margin is already locked in, expect markup on any change orders that come up during the build.

Cost-plus fee contract

A cost-plus fee contract reimburses the contractor for every actual project cost—labor, materials, equipment, subcontractors—and adds a fee on top. That fee is the contractor’s profit.

You’ll see two common fee structures. A cost-plus-fixed-fee pays the contractor a flat dollar amount regardless of what the project ends up costing. A cost-plus-percentage-of-cost ties the fee to total spend, which creates a problem—the more the project costs, the more the contractor makes.

This structure gives you maximum flexibility when the scope isn’t nailed down. It’s common for renovations, fast-tracked projects, or emergency work where you need to start before the full picture is clear. The downside is that you’re carrying the cost risk, so open-book accounting and audit rights should be written into the contract.

Time and materials contract

A time and materials (T&M) contract pays the contractor for actual labor hours at agreed-upon rates, plus the cost of materials with a markup. It’s the most flexible structure but also the least predictable when it comes to final cost.

T&M contracts work best for small or undefined projects—emergency repairs, exploratory demolition, maintenance work where nobody can reasonably estimate the scope up front. If you’re using one, push for a not-to-exceed clause that caps total spend. Without that ceiling, you’re writing a blank check.

The contractor submits timesheets and material receipts, and you reimburse based on the pre-agreed rates. Make sure the contract clearly defines what qualifies as reimbursable time and materials, or you’ll have that conversation later when the invoices start coming in.

Unit price contract

A unit price contract breaks the project into repeatable units of work—think cubic yards of concrete, linear feet of pipe, or square feet of flooring. The contractor bids a fixed price per unit, and the final contract price depends on how many units the project actually needs.

This is common in civil and infrastructure work where you can estimate quantities but won’t know the exact numbers until construction is underway. Road projects, utility installations, and earthwork typically use this structure.

Risk is shared here. The contractor carries the risk on each unit’s cost, and the owner carries the risk on total quantity. Watch out for unbalanced bids, where a contractor front-loads high prices on early work items and low prices on later ones.

Guaranteed maximum price contract

A guaranteed maximum price (GMP) contract is a cost-plus contract with a ceiling. The contractor gets reimbursed for actual costs plus a fee, but the total can’t exceed a pre-agreed maximum. If costs go over, the contractor absorbs the difference. If costs come in under, the savings are typically shared.

Think of it as a middle ground between cost-plus flexibility and lump sum certainty. It fits projects where the scope is mostly defined but not completely finalized, and the owner wants a budget guardrail before committing.

GMP vs. lump sum comes down to timing. A lump sum requires complete design documents before you can bid. A GMP sets a ceiling while the scope is still evolving, which gives you more flexibility but slightly less predictability.

The key detail to negotiate is how shared savings work. Make sure the contract defines what counts toward the GMP and how contingency funds get handled—otherwise you’ll disagree about it after the project wraps.

Design-build contract

A design-build contract puts both the design and construction phases under one contract with a single entity. Instead of hiring an architect first and then bringing in a separate contractor, you work with one firm that handles everything.

This creates a single point of responsibility. When something goes wrong, there’s no finger-pointing between the designer and the builder, because they’re the same team. It also tends to move faster, since construction can start before the design is fully finalized.

The trade-off is that you give up some control over the design process. In a traditional setup, you work closely with an architect before construction starts. With design-build, you need to trust the firm’s judgment on design decisions—or negotiate strong performance specifications up front.

Integrated project delivery contract

Integrated project delivery (IPD) is a multiparty agreement where the owner, architect, and contractor all sign one contract and share both risk and reward. If the project comes in under budget, everyone benefits. If it goes over, everyone takes the hit.

IPD works best on large, complex projects—hospitals, campuses, major infrastructure—where early collaboration between all parties can prevent expensive mistakes down the road. But it requires a high level of trust and transparency, and it’s not a great fit for teams that haven’t worked together before.

Contract type	Owner risk	Contractor risk	Best when scope is…	Price certainty
Lump sum	Low	High	Well-defined	High
Cost-plus	High	Low	Undefined or evolving	Low
Time and materials	Moderate-high	Low	Unclear or emergency	Low
Unit price	Moderate	Moderate	Defined by units	Moderate
GMP	Moderate	Moderate-high	Partially defined	Moderate-high
Design-build	Low-moderate	Moderate-high	Evolving with design	Moderate
IPD	Shared	Shared	Complex, collaborative	Variable

How to choose the right construction contract type

There’s no single contract type that works for every project. Your choice comes down to three things.

Scope clarity and change risk

This is the biggest factor. If the design is done and unlikely to change, lump sum gives both sides certainty. If the scope is still evolving, GMP or cost-plus gives you room to adapt. If nobody can define the scope yet, T&M gets work started while you figure it out.

Cost risk and price certainty

Lump sum puts nearly all cost risk on the contractor. Cost-plus and T&M put it on the owner. GMP and unit price split it—23% of firms have added price-sharing adjustments to contracts in response to tariffs alone, according to a report put out by the Associated General Contractors of America. Match your risk tolerance to the structure that fits.

Schedule pressure and delivery speed

Design-build lets construction start before the design is final. IPD gets everyone collaborating early so you avoid redesign delays later. Lump sum typically needs a complete design before bidding, which takes longer up front but reduces surprises.

Construction contract best practices that prevent disputes

Picking the right contract type is only half the work. How you manage the contract after signature matters just as much. Most construction disputes come from scope creep, payment disagreements, and changes that nobody documented properly.

• Define change order procedures up front: Specify who approves changes, what documentation is required, and how those changes affect price and schedule
• Track deadlines after signature: Payment milestones, insurance renewals, warranty periods, and notice deadlines all need proactive monitoring
• Centralize your contract documents: When plans, amendments, and signed contracts live across email threads and shared drives, disputes happen—52% of rework is caused by poor project data and miscommunication
• Use version control during negotiation: Redlines over email create confusion about which version is current

Contract lifecycle management (CLM) platforms automate a lot of this—routing contracts for approval, storing executed agreements in a searchable repository, flagging upcoming deadlines. That turns contract management from a manual scramble into a repeatable process.

Request a demo today to see how Ironclad helps teams manage contracts from signature through renewal.

Frequently asked questions about construction contract types

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Ironclad is not a law firm, and this post does not constitute or contain legal advice. To evaluate the accuracy, sufficiency, or reliability of the ideas and guidance reflected here, or the applicability of these materials to your business, you should consult with a licensed attorney.