(or design/build, and abbreviated D-B or D/B accordingly) is a construction project delivery system where, in contrast to traditional "design-bid-build" (or "design-tender"), the design and construction aspects are contracted for with a single entity known as the design-builder or design-build contractor. The design-builder is usually the general contractor, but in many cases it is also the design professional (architect or engineer). This system is used to minimize the project risk for an owner and to reduce the delivery schedule by overlapping the design phase and construction phase of a project. Where the design-builder is the contractor, the design professionals are typically retained directly by the contractor. Other attributes include
- Increased accountability by the service provider,
- Single source project delivery, and
- A value based project feedback system
Cost estimating for a design-build project is sometimes difficult because design documents are often preliminary and may change over the course of the project. As a result, design-build contracts are often written to allow for unexpected situations without penalizing either the Design-Builder or the owner. Several organizations (such as the Design/Build Institute of America) provide standardized form contracts for design-builders to use, but it is not unusual for the design-builder to provide its own contractual documents.
This uncertainty requires the owner to rely a great deal on the integrity, acumen, and competence of the design-builder. As the certainty of estimates decreases, the opinion of the construction professionals of the Design-Build firm must be trustworthy, accurate, and reasonably verifiable in order to minimize risk.
Single Source
Instead of having several contractors and consultants, an owner has just one entity to deal with. Design revisions, project feedback, budgeting, permitting, construction issues, change orders, and billing can all be routed through the design-build firm. This single point of contact allows a certain degree of flexibility for the owner Most design-builders will leverage that flexibility for the owner's benefit by continually refining the construction program to maximize the owner's value at the completion of the project.
Design-bid-build (or design/bid/build, and abbreviated D-B-B or D/B/B accordingly), also known as Design-tender (or "design/tender") and Traditional Method, is a project delivery method in which the agency or owner contracts with separate entities for each the design and construction of a project.
Design-bid-build is the traditional method for project delivery and differs in several substantial aspects from design-build.
There are three main sequential phases to the design-bid-build delivery method:
- The design phase
- The bidding (or tender) phase
- The construction phase
Value-based project feedback
Typically, in order for a contractor to bid on a project, very specific details relating to the methods and materials must be given to avoid any ambiguity and to make an "apples to apples" comparison of bids. In a design-build context, the owner, the owner's other consultants, and the design-builder can work together to determine what methods and materials will maximize the owner's value. In instances where marginally more expensive materials, designs, or construction methods might yield a higher return on investment for the owner than those of lower cost, the owner is free to adjust the project's program without having to re-bid the entire project.
Construction manager as constructor
Under this delivery method, a construction manager is hired prior to the completion of the design phase to act as a project coordinator and general contractor. Unlike the DBB method, a construction manager is hired during the design phase, which allows the construction manager to work directly with the architect and circumvent any potential design issues before completion of the construction documents. After documents are completed, the construction manager accepts bids for the various divisions of work from subcontractors or general contractors.
Negotiated
This delivery method is similar to the Design-Bid-Build method in that design and construction are performed by different firms. Unlike the design-bid-build approach, a general contractor and an architect are selected at the project’s inception. These firms work together throughout the design phase. When design documents are complete, the final construction costs are negotiated by the general contractor through bids from subcontractors on various scopes of work.
The design-builder is usually a general contractor, but in many cases it is also a design professional (architect or engineer). Design and build contractors employ professionals from the design and construction sector. Where the design-builder is a general contractor, the designers are typically retained directly by the contractor. Partnership may be created on a long term 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 anywhere else aspire to provide construction services, and one approach towards this goal is design-build. The AIA realised how design-build is becoming one of the main approach 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 - Finances -
Prefabricated house
Architect's fee
Architects' fee structures are typically based on a percentage of construction value, hourly rates or a fixed lump sum fee. Combinations of these structures are also common. Fixed fees are usually based on an a project's allocated construction cost and can range between 2 and 12% of new construction cost, depending on a project's size and complexity. Renovation projects typically command higher percentages, as high as 15-20%.
Overall billings for architectural firms range widely, depending on location and economic climate. Billings have traditionally been dependent on the local economic conditions but, with rapid globalization, this is becoming less of a factor for larger international firms. Salaries also vary, depending on experience, position within the firm (staff architect, partner or shareholder, etc.) and the size and location of the firm.
