(or design/build, and abbreviated D–B or D/B accordingly) is a project delivery system used in the construction industry.

It is a method to deliver a project in which the design and construction services are contracted by a single entity known as the design–builder or design–build contractor.

It can be subdivided into architect-led design–build (ALDB, sometimes known as designer-led design–build) and contractor-led design–build.

In contrast to "design–bid–build" (or "design–tender"), design–build relies on a single point of responsibility contract and is used to minimize risks for the project owner and to reduce the delivery schedule by overlapping the design phase and construction phase of a project.

"DB with its single point responsibility carries the clearest contractual remedies for the clients because the DB contractor will be responsible for all of the work on the project, regardless of the nature of the fault".

The traditional approach for construction projects consists of the appointment of a designer on one side, and the appointment of a contractor on the other side.

The design–build procurement route changes the traditional sequence of work.

It answers the client's wishes for a single point of responsibility in an attempt to reduce risks and overall costs.

It is now commonly used in many countries and forms of contracts are widely available.

Design–build is sometimes compared to the "master builder" approach, one of the oldest forms of construction procedure.

Comparing design–build to the traditional method of procurement, the authors of Design-build Contracting Handbook noted that: “from a historical perspective the so-called traditional approach is actually a very recent concept, only being in use approximately 150 years.

In contrast, the design–build concept—also known as the "master builder" concept—has been reported as being in use for over four millennia."

Although the Design-Build Institute of America (DBIA) takes the position that design–build can be led by a contractor, a designer, a developer or a joint venture, as long as a design–build entity holds a single contract for both design and construction, some architects have suggested that architect-led design–build is a specific approach to design–build.

Design-build plays important role in pedagogy, both at universities and in independently organised events such as Rural Studio or ArchiCamp.

The "design–builder" is often a general contractor, but in many cases a project is led by a design professional (architect, engineer, architectural technologist or other professional designers). Some design–build firms employ professionals from both the design and construction sector.

Where the design–builder is a general contractor, the designers are typically retained directly by the contractor. Partnership or a joint venture between a design firm and a construction firm may be created on a long-term basis or for one project only.

Until 1979, the AIA American Institute of Architects' code of ethics and professional conduct prohibited their members from providing construction services.

However today many architects in the United States and elsewhere aspire to provide integrated design and construction services, and one approach towards this goal is design–build.

The AIA has acknowledged that design–build is becoming one of the main approaches to construction.

In 2003, the AIA endorsed "The architect's guide to design–build services",[3] which was written to help their members acting as design–build contractors.

This publication gives guidance through the different phases of the process: design services, contracts, management, insurances, and finances.

On contractor-led design–build projects, management is structured so that the owner works directly with a contractor who, in turn, coordinates subcontractors.

Architects contribute to contractor-led design–build projects in one of several ways, with varying degrees of responsibility (where "A/E" in each diagram represents the architect/engineer):

Architect as employee of contractor:

The architect works for the contractor as an in-house employee.

The architect still bears professional risk and is likely to have less control than in other contractor-led design–build approaches.

Architect as a subcontractor:

Here, the architect is one of the many subcontractors on the team led by the contractor.

The architect bears similar professional risk but still with little control.

Architect as second party in contractor-led integrated project delivery (IPD):

The architect and contractor work together in a joint venture, both coordinating the subcontractors to get the project built.

The building owner has a single contract with this joint venture.

The contractor leads the joint venture so in supervising the subs, the architect might defer to the contractor.

The architect bears the same risk as they do in the traditional approach but has more control in IPD, even if they were to defer to the contractor.

Architect-led design–build projects are those in which interdisciplinary teams of architects and building trades professionals collaborate in an agile management process, where design strategy and construction expertise are seamlessly integrated, and the architect, as owner-advocate, project-steward and team-leader, ensures high fidelity between project aims and outcomes.

In architect-led design–build projects, the architect works directly with the owner (the client), acts as the designer and builder, coordinating a team of consultants, subcontractors and materials suppliers throughout the project lifecycle.

Architects lead design–build projects in several ways, with varying degrees of responsibility (where "A/E" in each diagram represents the architect/engineer):

Architect as provider of extended services:

Contracted to the owner, the architect extends his or her services beyond the design phase, taking responsibility for managing the subcontractors on behalf of the owner.

The architect bears similar risk but has more control over the project than in the traditional approach or on contractor-led design–build projects.

Architect as primary party in architect-led integrated project delivery (IPD):

Again, as in working together in a joint venture, both coordinating the subcontractors to get the project built.

Again, the building owner has a single contract with this joint venture.

This time, the architect leads the joint venture so in supervising the subs, the contractor might defer to the architect.

The architect might bear more risk than they do in the traditional approach but risk is shared with the owner and the contractor, as outlined in their agreement.

An alternative approach to effectuating this delivery structure is for the architect to contract directly with the owner to design and build the project, and then to subcontract the procurement and construction responsibilities to its allied general contractor, who enters into further subcontracts with the trades.

This is a difference in form, rather than in substance, because the business and legal terms of the agreement between the architect and the general contractor may be the same regardless of whether they are characterized as a joint venture or as a subcontract.

It is the "flip side of the coin" of the contractor-led approach described above in which the general contractor subcontracts the design to the architect.

Architect as full service leader of design build process:

Contracted to the owner, the architect offers full service to the owner, taking responsibility for managing the subcontractors, consultants and vendors, and involving them throughout the project, start to finish, from design through construction.

The architect's role shifts during the project, from designer to site supervisor (effectively taking the role of a general contractor), but monitors the project vision, and is able to call upon subcontractors' construction expertise throughout.

The architect bears the greatest risk but also has more control over the project than in either the traditional approach, or in the contractor-led and other architect-led design–build projects.

A single set of integrated contracts combining design and construction responsibilities, rather than two discrete contracts for each, acknowledges the interdependence of the architects' and construction trades' project responsibilities, and reduces the likelihood of disputes.