Usually not: a main contractor is not liable for defective design produced by a nominated or named subcontractor unless the contract expressly makes it so, and no such duty is readily implied; the contractor carries the design only where the contract says so, on design and build, or under a performance-specified regime

Usually not. A main contractor is not liable for design produced by a nominated or named subcontractor unless the contract clearly makes it so. Where the main contract says nothing about the contractor carrying design responsibility, the courts will not readily imply one, particularly where the design was developed by the specialist and the design team without the contractor's involvement. The standard forms confirm this: the common engineering conditions limit the contractor's design obligation to what is expressly stated, and the older building form made clear the contractor was not responsible for a nominated subcontractor's design; the current building form has no nomination at all. The contractor does carry the design where the contract expressly says so, on design and build, and under a performance-specified regime. The safe course for an employer is to take a design warranty directly from the subcontractor that did the design.