Construction Contracts
Understanding the types of construction contracts and the essential contract documents.
Definition of a Construction Contract
A construction contract is a legally binding agreement between a client (owner) and a contractor to execute a specific project. The choice of contract type heavily influences how risk is distributed between the parties.
Types of Construction Contracts
Different project scopes and risk tolerances dictate the use of different contract types.
Lump Sum (Fixed Price) Contract
The contractor agrees to perform the entire scope of work for a single, fixed price.
- Risk: The contractor bears the majority of the risk. If the project costs more than anticipated, the contractor's profit is reduced. If it costs less, their profit increases.
- Best for: Projects with a well-defined scope of work and complete design documents before bidding.
Unit Price Contract
The contract is based on estimated quantities of specific items of work (e.g., cubic meters of concrete, linear meters of pipe) and a fixed price per unit.
- Risk: Risk is shared. The owner risks the total cost increasing if quantities are higher than estimated. The contractor risks losing money if their unit price was estimated too low.
- Best for: Projects where the exact quantities of work cannot be determined accurately before construction begins (e.g., earthworks, road construction).
Cost Plus (Time and Materials) Contract
The owner agrees to pay the contractor for all actual costs incurred (labor, materials, equipment) plus a predetermined fee (either a fixed amount or a percentage of the costs) to cover overhead and profit.
- Risk: The owner bears the majority of the risk, as the final cost is unknown.
- Best for: Projects where the scope of work is poorly defined or highly variable, and time is of the essence. Often includes a "Guaranteed Maximum Price" (GMP) to cap the owner's risk.
Standard Contract Documents
A complete construction contract is not just a single signature page. It consists of several integrated documents.
Essential Documents
Checklist
- Agreement (Contract Agreement): The overarching document signed by both parties summarizing the project, price, and schedule.
- General Conditions: Standard terms outlining the rights, responsibilities, and relationships of the owner, contractor, and engineer (e.g., handling changes, payments, dispute resolution).
- Special/Supplementary Conditions: Modifications or additions to the General Conditions tailored to the specific project requirements (e.g., site-specific security rules).
- Specifications: Detailed written descriptions of the materials, workmanship, quality standards, and execution methods required.
- Drawings (Plans): Graphic representations showing the location, dimensions, and details of the work.
- Bill of Quantities (BOQ): An itemized list of materials, parts, and labor (primarily for unit price contracts).
- Addenda: Changes or clarifications issued before the contract is signed (during bidding).
- Contract Modifications (Change Orders): Written agreements to modify the scope, cost, or time after the contract is signed.
Bonds and Guarantees
To mitigate financial and performance risks, owners often require contractors to provide various forms of security.
Types of Security
Checklist
- Bid Security (Bid Bond): Ensures that the winning bidder will actually sign the contract and provide the necessary performance bonds. If they back out, the owner keeps the bond.
- Performance Bond: Guarantees that the contractor will complete the project according to the plans and specifications. If the contractor defaults, the surety company steps in to finish the job or pay the owner.
- Payment Bond: Guarantees that the contractor will pay their subcontractors, laborers, and material suppliers, protecting the owner from mechanic's liens.
- Guarantee Bond (Warranty Bond): Covers defects in materials or workmanship that arise during the warranty period (usually 1 year) after project completion.
- Advance Payment Bond: If the owner provides an advance payment (mobilization fee), this bond guarantees the contractor will use the funds for the project. It is amortized as the project progresses.
- Retention Money: Not a bond, but a standard practice where the owner retains a percentage (usually 10%) of each progress payment until the project is completed and accepted, serving as a fund to correct any immediate defects.
FIDIC Standard Forms of Contract
For international construction projects, standardized forms of contract are frequently used to provide a globally recognized framework for risk allocation and dispute resolution. The most recognized of these is published by FIDIC (Fédération Internationale Des Ingénieurs-Conseils, or the International Federation of Consulting Engineers).
The FIDIC 'Rainbow Suite'
FIDIC contracts are color-coded based on the type of project and risk allocation strategy:
- Red Book: Conditions of Contract for Construction. Used for building and engineering works designed by the Employer (or by the Engineer on behalf of the Employer). Payment is typically on a re-measurement basis (Unit Price).
- Yellow Book: Conditions of Contract for Plant and Design-Build. Used for electrical and mechanical plant, and for building and engineering works, designed by the Contractor. Payment is usually a lump sum.
- Silver Book: Conditions of Contract for EPC/Turnkey Projects. Suitable for process/power plants and infrastructure where a high degree of certainty of final price and time is required. The Contractor takes total responsibility for the design and execution.
- Green Book: Short Form of Contract. Recommended for engineering and building work of relatively small capital value or for relatively simple or repetitive work.
Key Takeaways
- Lump Sum: Fixed price, high contractor risk, requires complete design.
- Unit Price: Paid based on actual quantities measured in the field, common in heavy civil work.
- Cost Plus: Reimburses actual costs plus a fee, high owner risk, best for undefined scopes.
- A construction contract is a collection of documents, including the Agreement, General Conditions, Specifications, and Drawings.
- In case of a discrepancy between drawings and specifications, standard general conditions usually state that the specifications govern.
- Bonds (Bid, Performance, Payment, Guarantee) shift the risk of contractor default from the owner to a surety company.
- Retention money provides an immediate fund for the owner to fix defects during construction and the warranty period.
- The FIDIC standard forms provide a widely accepted international framework for construction contracts.
- The Red Book is typically for employer-designed projects (Unit Price), the Yellow Book for design-build, and the Silver Book for EPC/Turnkey projects where the contractor bears maximum risk.