Why Choose Design & Build? Process, Benefits & Risks

Introduction

When planning a major home renovation, extension, or even a new build, one of the earliest and most critical decisions you’ll face is choosing the right project delivery method. Traditionally, homeowners have followed a design-bid-build model: working with an architect to produce designs, tendering those designs to contractors, and then managing separate entities throughout the build. In recent decades, however, the design and build model has gained ground in both the UK and internationally as an increasingly effective approach. But what exactly makes design and build different, and what are its advantages and risks?

What is the Design & Build Model?

Design and build is a procurement method in which the client contracts with a single company that is responsible for both the design and construction phases of the project. This single point of responsibility streamlines the process, integrates design with construction expertise, and reduces fragmentation between teams.

Unlike traditional procurement, which can involve multiple contracts and sometimes conflicting interests, the design-and-build model aims for a more collaborative approach that prioritises efficiency, cost predictability, and speed.

Key Benefits

1. Single Point of Responsibility

The client only needs to manage one contract with one entity. This eliminates the risk of disputes between the architect and the contractor, a problem that often plagues traditional models.

2. Faster Project Timelines

The Design-Build Institute of America (DBIA) cites research showing that design-build projects are delivered 33% faster on average than traditional design-bid-build projects. The ability to overlap design and construction activities accelerates delivery.

3. Cost Certainty and Efficiency

Because the contractor is engaged early, cost estimates are provided from the beginning, reducing the likelihood of surprises later on. According to UK research on Early Contractor Involvement, projects can achieve around 7% cost savings compared to traditional methods.

4. Improved Collaboration and Innovation

When the design and construction teams are part of the same organisation, innovation is easier to foster. Value engineering can be applied from the outset, ensuring that design decisions align with buildability and budget.

Potential Risks

1. One criticism of design-build is that the architect’s role may be diminished, potentially leading to cost-driven compromises in design quality.

2. Risk of Cost Overruns through Lock-In

Research into “lock-in” effects highlights that early commitment to a contractor’s methods or materials can make it hard to change course later. This can sometimes lead to overruns or less optimal outcomes.

3. Client Knowledge Gap

Because so much responsibility lies with the design-builder, it’s important for clients to fully understand their needs at the outset. If requirements change mid-project, flexibility may be more limited than in a design-bid-build scenario.

Who Should Consider Design & Build?

Homeowners looking for extensions, large-scale renovations, or new builds where cost and timeline certainty are a priority will benefit most. For clients who value design excellence above all else, careful selection of a design-build firm with strong architectural credentials is key.

Conclusion

The design-and-build model offers streamlined project delivery, strong cost predictability, and faster timelines. However, clients should weigh these benefits against potential risks and ensure they select an experienced design-build partner with both architectural and construction expertise. With the right team, this approach can deliver a smoother, less stressful journey from concept to completion.

References for Further Reading:

• Design-Build Institute of America – New Research Shows Design-Build Continues to Deliver Projects Most Efficiently
• The Design-Build construction method – Bild
• UK Government & CIBSE reports on project procurement and Early Contractor Involvement.