The General Liability Gap Hiding Inside Every Design-Build Job

General liability was written for one kind of mistake: the pipe leaks because it was installed wrong, the slab cracks because it was poured wrong, the wall fails because someone on the crew missed a step. It was never written for the mistake that shows up more often as delivery methods shift — the wall leaks because of how it was specified, not how it was installed. That's a different exposure, covered by a different policy, and a lot of contractors don't carry it.

Where "construction" quietly becomes "design"

A construction defect is a means-and-methods failure — you built it wrong. A design error is a judgment failure — someone decided how a system should perform, and that decision was wrong. The problem is how easily ordinary GC work crosses that line without anyone flagging it:

Notice what's on that list: nothing exotic. Value-engineering a spec, writing shop drawings that carry real engineering content, running a delegated-design sub, making a field call so a detail actually works — every mid-sized GC does some version of this on most jobs. None of it looks like "design" from inside the job. All of it is design, in the sense that matters when a claim gets filed and a carrier reads the exclusions.

Why this is getting more common, not less

This isn't a rare edge case getting rarer. Design-build — the delivery method that structurally pushes design-adjacent decisions into the contractor's scope — is projected to account for $2.6 trillion in U.S. construction spending between 2024 and 2028, nearly half of the $5.5 trillion total the forecast tracks.

Owners buy design-build for speed, and 102% faster than design-bid-build is a real number worth chasing. But speed comes from collapsing the separation between the entity that designs and the entity that builds — and insurance programs written for the old separation don't automatically catch up just because the contract did.

What actually closes the gap

Three things, none of them complicated:

• Ask the coverage question before the contract question. Before signing anything with delegated design, performance specs, or design-assist language, find out from your broker whether your program already includes contractors errors & omissions (professional liability) coverage — and if not, what it costs to add relative to the size of the exposure on that specific job.
• Treat E&O as a complement, not a replacement. General liability still does its job on installation defects. The fix is carrying both, not swapping one for the other.
• Document the decision, not just the outcome. Every substitution, every field modification, every judgment call embedded in a shop drawing should have a paper trail showing who made the call, when, and why. That record is what turns a dispute years later into a defensible position instead of a guess about who decided what.

None of this requires slowing down design-build work or turning down the jobs that use it. It requires knowing which of the routine things your teams do every week are quietly outside what your current policy was written to cover — and closing that specific gap before a claim tests it instead of after.

Sources

1. General liability is written to cover construction defects (bad installation), not professional-services exposure (bad design decisions); the gap opens when contractors take on delegated design, performance-spec substitutions, or engineered shop drawings under design-build and similar delivery methods: IA Magazine, 'Beyond General Liability: How to Spot Contractors' Hidden Design Risk' by John Immordino, SVP Professional Liability at Arlington Roe (August 17, 2026) — source
2. Design-build is projected to account for $2.6 trillion in U.S. construction spending from 2024–2028 — nearly half of the $5.5 trillion total construction forecast for the segments it tracks — and design-build projects are delivered 102% faster on average than design-bid-build: DBIA, '2025 Design-Build Data Sourcebook' (February 14, 2025) — source