This Practice Note is a ‘how to’ guide on drafting a construction sub-contract which is ‘back-to-back’ with a main contract. Sub-contracting essentially means a contractor entrusting a third party to perform some of its obligations under the main contract. The objective in drafting a sub-contract must therefore be to ensure that the sub-contractor’s obligations to the contractor are identical to (or at least, no less onerous than) the contractor’s obligations to the client—in other words, to ensure that the sub-contract mirrors, or is ‘back-to-back’ with, the main contract. This guide sets out the steps you will need to run through in drafting a sub-contract, to ensure an effective step-down of obligations from contractor to sub-contractor, assuming that the main contract is a typical bespoke design and build contract. If the main contract is, or is based on, a standard form construction contract such as the JCT Design and Build Contract 2024 or the NEC Engineering and Construction Contract, it may be sensible to consider using the corresponding standard form subcontracts as a base. For more