Design-Build Lean Addendum - 431

The ConsensusDocs 431 Design-Build Lean Addendum is the industry’s first and only standardized contract document specifically designed to incorporate Lean construction practices into the design-build project delivery method. As construction trends shift toward efficiency, collaboration, and value-based outcomes, this addendum offers a powerful tool to bring Lean methodologies into your contractual framework—without committing to a full Integrated Project Delivery (IPD) model.

This Lean Addendum is intended to be attached to prime design-build agreements, such as:

• ConsensusDocs 400 – Preliminary Agreement
• ConsensusDocs 410 – Cost of Work Plus Fee with GMP
• ConsensusDocs 415 – Lump Sum Agreement

It can also be used with design professional agreements (ConsensusDocs 420) and subcontractor agreements (ConsensusDocs 450 and ConsensusDocs 460), ensuring that Lean principles flow down throughout the entire project team.

The 431 Addendum outlines Lean tools and techniques such as:

• Pull planning and collaborative scheduling
• Target value design
• Last planner system
• Big room (co-location) meetings
• Continuous improvement and constraint removal
• Real-time decision-making and accountability frameworks

By formalizing these Lean practices within the contract, teams can minimize waste, enhance communication, align goals, and deliver projects more efficiently. This is especially valuable for Owners and Design-Builders seeking the benefits of Lean without transitioning to a full IPD model like ConsensusDocs 300.

Unlike traditional design-build contracts that may support collaborative behaviors but lack contractual enforcement of Lean methods, ConsensusDocs 431 ensures clarity and commitment to these practices. It also encourages early stakeholder involvement, which reduces rework, shortens timelines, and improves budget control.

Whether you’re looking to improve outcomes, foster innovation, or align your team under a shared vision of continuous improvement, the ConsensusDocs 431 Lean Addendum is an essential addition to your design-build agreement toolkit.