What Is a Cost Plus Construction Contract?

A cost plus construction contract is a construction agreement where the contractor is paid for all project costs plus an additional fee or percentage for profit. This pricing model allows flexibility when the project scope is not fully defined.

Instead of agreeing to a fixed price upfront, the total cost is based on:

• Actual labor and material costs
• Project expenses
• A contractor fee (fixed fee or percentage)

This type of cost plus contract is commonly used when the full scope of a construction project is not clearly defined at the start.

How Cost Plus Construction Works

In a typical cost plus construction contract, the total price is made up of two parts:

• Direct Costs: Labor, materials, equipment, subcontractors
• Contractor Fee: A fixed fee or percentage added on top

For example:

• Labor and materials: $200,000
• Contractor fee (10%): $20,000
• Total project cost: $220,000

Because pricing is flexible, this model is often referred to as cost plus pricing.

Cost Plus Construction Contract Example

Here’s a simple example of how a cost plus construction contract agreement works in practice:

A developer hires a contractor to build a commercial space, but final design details are still evolving.

The agreement states:

• All actual construction costs will be reimbursed
• The contractor will receive a 12% fee on total costs

During the project:

• Total construction costs reach $500,000
• Contractor fee = $60,000

Final contract price: $560,000

If costs increase due to changes or delays, the total price also increases.

This flexibility is why cost plus contracts are widely used but also why they require careful legal structuring.

How Cost Plus Pricing Works in Construction

Cost plus pricing allows contractors to recover all legitimate project expenses while earning a profit.

There are several common pricing structures:

1. Cost Plus Fixed Fee

• Contractor receives a set fee regardless of total cost
• Provides more predictability for the owner

2. Cost Plus Percentage

• Contractor earns a percentage of total project costs
• Can create incentives for higher spending

3. Cost Plus with Guaranteed Maximum Price (GMP)

• Total cost is capped at a maximum amount
• Balances flexibility with cost control

Understanding which structure applies is critical when entering into a construction contract agreement.

Advantages of Cost Plus Construction Contracts

Cost plus contracts offer several benefits:

• Flexibility when project scope is uncertain
• Higher quality control since materials aren’t restricted by fixed budgets
• Transparency with itemized cost tracking
• Faster project start without final pricing delays

This makes cost plus construction especially useful for complex or evolving projects.

Disadvantages and Risks

Despite the advantages, cost plus contracts carry real risks:

• Unpredictable final cost
• Limited cost control for owners
• Potential disputes over what qualifies as a reimbursable expense
• Incentive misalignment if contractor profit increases with cost

Without clear contract terms, these issues can lead to serious legal disputes.

Cost Plus vs Lump Sum vs GMP Contracts

Understanding how cost plus compares to other contract types is essential:

Cost Plus Contract

• Flexible pricing
• Owner bears most cost risk

Lump Sum Contract

• Fixed total price
• Contractor bears cost overruns

Guaranteed Maximum Price (GMP)

• Costs reimbursed up to a cap
• Shared risk between parties

Each structure serves a different purpose depending on the project and risk tolerance.

What Should Be Included in a Cost Plus Construction Contract Agreement?

A well-drafted cost plus construction contract agreement should clearly define:

• Scope of work
• Contractor fee structure (fixed or percentage)
• Definition of reimbursable costs
• Documentation and reporting requirements
• Change order procedures
• Payment schedule
• Dispute resolution terms

Clear terms reduce misunderstandings and protect both parties.

Legal Risks in Cost Plus Construction Contracts

From a legal perspective, cost plus contracts often lead to disputes when terms are vague or poorly defined.

Common issues include:

• Disagreements over “reasonable” costs
• Lack of documentation for expenses
• Scope creep without proper approvals
• Payment disputes between owners and contractors

Working with a construction attorney helps ensure your construction contract agreement is structured to minimize these risks.

When Should You Use a Cost Plus Contract?

A cost plus construction contract is best used when:

• Project scope is uncertain or evolving
• Design is incomplete at the start
• Flexibility is more important than strict budgeting
• The owner trusts the contractor’s cost management

For straightforward projects with clearly defined scope, a fixed-price contract may be more appropriate.

Speak With a Construction Contract Attorney

Cost plus construction contracts can be effective but only when structured correctly.

At Southron Firm, we help businesses:

• Draft and review construction contract agreements
• Identify and reduce legal risk
• Resolve construction disputes

If you are entering into a cost plus contract, our attorneys can help protect your interests from the start.

FAQs About Cost Plus Construction Contracts

Is a cost plus contract better than a fixed-price contract?

It depends on the project. Cost plus contracts offer flexibility, while fixed-price contracts provide cost certainty.

Who benefits most from cost plus contracts?

Contractors often benefit from reduced financial risk, while owners benefit from flexibility and transparency.

Are cost plus construction contracts risky?

They can be if not properly structured. Clear terms and cost controls are essential to reduce risk.