Debate on the merits of design–build vs. design–bid–build
The rise of design–build project delivery has threatened the traditional hierarchies and silos of the design and construction industry. As a result, a debate has emerged over the value of design–build as a method of project delivery. Critics of the design–build approach claim that design–build limits the clients' involvement in the design and allege that contractors often make design decisions outside their area of expertise. They also suggest that a designer—rather than a construction professional—is a better advocate for the client or project owner and/or that by representing different perspectives and remaining in their separate spheres, designers and builders ultimately create better buildings. Proponents of design–build counter that design–build saves time and money for the owner, while providing the opportunity to achieve innovation in the delivered facility. They note that value is added because design-build brings
value engineering into the design process at the onset of a project. Design–build allows the contractor, engineers and specialty trade contractors (subcontractors) to propose best-value solutions for various construction elements before the design is complete. Design–build brings all members of a project team together early in the process to identify and address issues of cost, schedule and constructability. Proponents suggest that as a result, design-build alleviates conflict between architects and contractors and reduces owner risk for design errors. They argue that once design is finalized and construction begins, the greatest opportunity to achieve cost savings has already been lost, and the potential for design errors is greater, leading to change orders that create cost growth and schedule delays. Proponents note that design–build allows owners to avoid being placed directly between the architect/engineer and the contractor. Under design–bid–build, the owner takes on significant risks because of that position. Design–build places the responsibility for design errors and omissions on the design–builder, relieving the owner of major legal and managerial responsibilities. The burden for these costs and associated risks are transferred to the design–build team. The cost and schedule reduction and decreased
litigation associated with design–build project delivery have been demonstrated repeatedly. Researches on
Selecting Project Delivery Systems by Victor Sanvido and Mark Konchar of Pennsylvania State University found that design–build projects are delivered 33.5% faster than projects that are designed and built under separate contracts (design-bid-build). Sanvido and Konchar also showed that design–build projects are constructed 12% faster* and have a unit cost that is 6.1% lower than design-bid-build projects. Similar cost and time savings were found in a comparison study of design–build, and design-bid-build for the water/wastewater construction industry, a peer-reviewed paper authored by Smith Culp Consulting that will be published in July 2011 by the American Society of Civil Engineers. A benchmarking and claims study by Victor O. Schinnerer, one of the world's largest firms underwriting professional liability and specialty insurance programs, found that, from 1995 to 2004, only 1.3% of claims against A/E firms were made by design–build contractors. Advantages have been summarized as: • Efficiency: Typically led by contractors, 'design–build' has evolved as an efficient way to deliver projects primarily where the building project goals are straightforward, either constrained by budget, or the outcome is prescribed by functional requirements (for example, a highway, sports facility, or brewery). Construction industry commentators have described design–build as a high performance 'construction project delivery system', a dynamic approach to making buildings that presents an alternative to the traditional design-bid-build approach. • Single-source: Design–build is growing because of the advantages of single-source management: Unlike traditional design-bid-build, it allows for the owner to contract with just one party who acts as a single point of contact, is responsible for delivering the project and coordinates the rest of the team. Depending on the phasing of the project, there may be multiple sequential contracts between the owner and the design–builder. The owner benefits because if something turns out to be wrong with the project, there is a single entity that is responsible for fixing the problem, rather than a separate designer and constructor each blaming the other.
Advantages for less-prescriptive projects Architect-led design–build is suited primarily to less prescriptive architectural projects (private residences, non-profit institutions, museums), for the efficiencies it yields and the sophisticated design interpretation it affords, particularly: • Where the primary project goals are design-driven or visionary rather than prescribed by budgetary constraint or functional requirements • Where the project is specifically "Capital A"-artistically/creatively driven, in a way that traditionally yields the highest level of cost overruns. • Where the efficiencies of design–build approach and an architect's interpretive skill are equally important These less prescriptive projects need not be stuck with the "broken buildings and busted budgets" described by Barry Lepatner. Rather, the less prescriptive the project, the more the client needs an architect to steward an emergent design from vision to completion. So it follows that for the broadest range of building projects, the rigors of architect-led design–build is compelling and preferable where design is of paramount importance to the client.
Recursive knowledge The process and the knowledge it produces is recursive: Since subcontractors are engaged early and often in an architect-led design build project, to assess efficiencies,
opportunity costs, payback rates and quality options. Their input informs overall design decisions from the outset. Cost-benefit is also a constant consideration that informs design decisions from the outset. Building performance is measured early too, so that trade offs between budget, schedule, functionality and usability can inform specification and continuous refinement of the design. Architects engaged in this dynamic process understand and keep up to date with the potential of contemporary technology and materials available to building professionals, and translate what they learn into their design work. This knowledge is fed back, not just to the specific project but can be shared to other project teams, throughout a studio, or more broadly to the profession, and can become an active source of insight in and of itself. ==Growth of design–build method==