A design-build firm wins a $4 million commercial project. The contract is signed, the team is mobilized, and the work proceeds without incident through eleven months of construction. Nine months after substantial completion, the building’s waterproofing system fails. Water intrusion causes significant interior damage. The investigation reveals a design specification error in the waterproofing system detail.
The owner files a claim against the design-build firm. The firm’s commercial general liability carrier reviews the claim and invokes the professional services exclusion, the standard GL provision that bars coverage for property damage or bodily injury arising from the rendering or failure to render professional services. The design specification error is a professional services failure. The GL policy will not respond to it.
The firm does not carry professional liability insurance. The contract’s insurance specification required only general liability, workers compensation, and commercial auto. Nobody thought to require professional liability or to evaluate whether the firm’s GL policy would actually respond to the specific type of claim that integrated design and construction make most likely.
Why Design-Build Contracts Create Insurance Requirements That Traditional Contracts Do Not
In traditional design-bid-build project delivery, the architect carries professional liability for the design, and the contractor carries general liability for the construction. Each party’s coverage corresponds to their scope. When something goes wrong, the investigation determines whether the failure was a design error or a construction defect, and the appropriate policy responds.
Design-build delivery merges those scopes under a single entity and a single contract. That merger concentrates both the design liability and the construction liability in one organization. The design-build entity’s GL policy excludes professional services. Its professional liability policy, if one exists, covers the design services component. When a claim involves both a design error and a construction failure, as many design-build claims do, both policies must be in place for the coverage picture to be complete.
The insurance specification in a design-build contract must reflect this integrated liability structure. A specification that mirrors traditional design-bid-build requirements, including GL, workers’ compensation, and auto, leaves the professional liability gap completely unaddressed. That gap does not exist in a traditional contract because the architect carries their own professional liability. In a design-build structure, the entity that designed the project also built it, and the professional services exclusion in its GL policy applies to both components of a claim that alleges the design caused the damage.
Five Elements Every Design-Build Insurance Specification Should Address
Professional liability coverage requirement: The insurance specification must explicitly require the design-build entity to maintain professional liability coverage, commonly called errors and omissions insurance in the design context. The required limit should reflect the design fee exposure and the potential scale of design-error claims on the project. A $4 million construction contract with a $400,000 design fee component warrants a meaningful professional liability limit, not the minimum available.
GL policy professional services exclusion review: Before accepting a certificate of insurance from a design-build contractor, the project owner should request confirmation that the GL policy does not contain a professional services exclusion that would bar coverage for design-related claims. Some GL policies are specifically endorsed to remove or limit this exclusion for design-build contractors. Where the exclusion remains, professional liability must provide the coverage the GL policy explicitly declines.
Additional insured endorsements on both policies: Additional insured status on the design-build entity’s GL policy gives the project owner direct access to that coverage for construction-related claims. Additional insured status on the professional liability policy is more complex because many PL policies do not extend additional insured status in the same way GL policies do. Understanding the specific endorsement language and what it provides before a claim occurs prevents disputes about access at the time the coverage is most needed.
Tail coverage requirements for professional liability: Professional liability policies are claims-made, meaning the policy in force when a claim is reported, not when the alleged error occurred, is the policy that responds. If the design-build entity’s professional liability policy lapses or is not renewed after project completion, claims arising from design errors discovered after policy cancellation may have no coverage. The contract should specify a tail coverage period, typically three to five years for construction projects, longer for complex infrastructure, to ensure that post-completion claims have a responding policy.
Subcontractor insurance flow-down requirements: Design-build contracts frequently involve design subconsultants, specialty subcontractors, and trade contractors whose scope contributes to both the design and construction components of the project. The prime contract’s insurance specification must flow down appropriate requirements, including professional liability where subcontractors provide design services, and the design-build entity must be held responsible for verifying and documenting compliance. A design specification error caused by a structural engineer subconsultant creates liability that flows through the prime design-build entity regardless of whether the subconsultant carries adequate coverage.
Tooher-Ferraris works with design-build contractors and project owners to review contract insurance specifications, identify professional liability gaps, and structure coverage programs that match the integrated liability profile of design-build project delivery. Learn more at https://toofer.com/commercial-insurance/ and https://toofer.com/specialty-programs/.
RIMS, the risk management society, publishes resources on design-build risk management and contract insurance requirements at rims.org. The Design-Build Institute of America provides guidance on standard design-build contract forms and their insurance implications at dbia.org.
Frequently Asked Questions
Why does a design-build contract need professional liability requirements when the firm also has GL?
General liability policies contain a professional services exclusion that bars coverage for claims arising from design errors, specifications, or professional advice. In a design-build project, design error claims are the type most likely to arise from the integrated delivery model, yet they are excluded from GL coverage. Professional liability insurance is required to cover the design exposure that the GL policy explicitly declines.
What is tail coverage and why does it matter in a design-build contract?
Professional liability insurance is a claims-made policy that covers claims reported during the policy period. Tail coverage, also called an extended reporting period endorsement, extends the window for reporting claims after the base policy lapses or is not renewed. For design-build projects, where latent design defects can emerge years after substantial completion, a contractually required tail period of three to five years ensures that post-completion claims have a responding policy, rather than falling into a coverage gap created by policy cancellation.
How should additional insured requirements be structured for design-build professional liability?
Professional liability additional insured endorsements operate differently from GL endorsements. Many PL carriers do not extend additional insured status in the traditional sense. The contract should specify the protections the project owner requires, such as access to coverage for design claims, direct action rights against the PL policy, or similar protections. The design-build entity should then verify what its specific PL policy actually provides before representing that it is compliant. Mismatches between contract requirements and actual policy language are among the most common design-build insurance disputes.
Ready to review your design-build contract insurance requirements? The team at Tooher-Ferraris has been helping contractors structure complete construction insurance programs since 1932. Contact us today to schedule a no-obligation consultation — https://toofer.com/contact-us/
