Design-build (or design/build, and abbreviated D-B or D/B accordingly) is a construction project delivery system where, in contrast to "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. The most efficient design-builder has design and construction professionals working directly for the same at-risk entity. This is one of the oldest forms of construction since developing from the "master builder" approach.
The design/build delivery system often cites the original "Master Builder" model used to build most pre-modern projects. Under the Master Builder approach, a central figure of the architect held total project accountability. From inception to completion, the master builder was the key organizational figure and strictly liable to the owner for defects, delays, and losses. The design/build system is a return to some of the fundamentals of the Master Builder approach. For nearly the entire twentieth century, the concept of Design-Build was classified as a non-traditional construction method in the United States, which is the last country to still embrace the old standard of Design-Bid-Build.
Overview of process Edit
Design-build focuses on combining the design, permit, and construction schedules in order to streamline the traditional design-bid-build environment. This does not shorten the time it takes to complete the individual tasks of creating construction documents (working drawings and specifications), acquiring building and other permits, or actually constructing the building. Instead, a design-build firm will strive to bring together design and construction professionals in a collaborative environment to complete these tasks in an overlapping like fashion i.e. construction has begun while the building is still being designed.
Typically the hallmark of a Design/Build project is that one organization is responsible for both design and construction of the project. If this organization is a contractor, the process is known as "Contractor-led Design-Build". If the organization is a design firm, the process is known as "Design-led Design-Build". In either case, the organization employed by the owner rarely handles both aspects of design and construction in-house. In fact, the organization often subcontracts with on-site personnel (if design-led) as well as architects and engineers (if contractor-led).
Potential problems of design-build Edit
Potential problems of the design-build process include:
- Premature cost estimating,
- a short-cut design process,
- decreased accountability by the service provider, and
- correction of work.
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, and the price of the completed project may vary greatly from the original estimate.
The uncertainty of the early estimate requires the owner to rely a great deal on the integrity, acumen, and competence of the design-builder. As the certainty of estimate decreases, the reputation of the design-build firm becomes more important. Estimates should be accurate, and reasonably verifiable in order to minimize risk.
The short-cut design process may restrict regulatory review efforts to a potentially cursory overview. Projects may be designed as they are built, thus providing those with the responsibility of oversight little to no time at all to review completed plans and specifications. Projects completed before they may be reviewed can be forced into costly change orders to bring the project into compliance with regulatory requirements. It may here be noted that the "design-bid-build" method frequently results in a trip "back to the drawing board" based on the tendency of many architects to lack familiarity with actual current costs related to the realization of a built project.
The short-cut design process may also create an ill-defined scope of the work. Since the purpose of the design documents is to describe the project's desired outcome, an abbreviated design process can result in leaving out some details of the quality, workmanship, and/or desired aesthetic attributes of the project, thus making it impossible to hold the builder accountable for the desired level of quality. Once again, the owner must rely on the reputation of the design-builder for a satisfactory product.
decreased accountability- The design-builder is given a great deal of control over the entire process, both of how the project is configured and how it is completed. With no third-party observer such as an independent architect to administer the process and advocate for the Owner, the unscrupulous design-builder may sacrifice the quality of materials and systems such as HVAC, lighting, plumbing, and even structural elements in order to pad profits or shave time at the expense of the owner.
correction of work- Since the owner may not have the expertise to evaluate the quality of portions of the work, he/she must trust the design-builder to properly design a facility that will meet the needs of the owner, and to execute the design properly, according to codes, and consistent with industry-standard specifications. Unless the builder agrees with the owner's assessment of the situation, the owner with-out the normal representation of a design professional may have no means to understand the contractural requirements on which to inforce a correction of work done improperly, incompletely or poorly or a contractor-caused delay. In these cases which are a normal part of most projects, the Owner is thus left to go to some form of formal dispute resolution such as litigation, or arbitration.
In exchange for the ability to more firmly establish a construction budget, the owner assumes the risk and responsibility to review contract documents, such as plans, specifications, and agreements for services, and to hold the design-builder accountable to design and deliver a quality product on schedule. By contrast, under the typical design-bid-build or negotiated project delivery system the architect who created the Contract Documents is in a better position to reject work not performed according to the standards set forth in the plans and specifications.
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. Architectural societies, such as the American Institute of Architects , warn that when non-standard documents are used, great caution should be exercised because they may be untested, or may be written to favor one party or the other; Therefore, qualified legal counsel should be employed to review all contracts before signing.
Benefits of design-build Edit
It is important to note that the design-build method, while not focused on saving the owner construction costs, nonetheless often saves the owner money on the overall project. The combined effects of carrying a construction loan (which typically carries a higher interest rate than permanent financing) and an earlier useful on-line date usually yields considerable overall value to the project and may make seemingly unfeasible projects into genuine opportunities.
The compression is an important aspect of the implementation of this system. Other potential attributes include:
- enhanced communication between the service provider and the client,
- increased accountability by the service provider,
- single source project delivery, and
- a value based project feedback system
Enhanced communication Edit
Because the design parameters of a project are being developed along with the budgetary goals - construction methodologies and budget conditions being weighed simultaneously - a project is more likely to be realized than with a pure design approach. The owner has greater access to the project "team" as the project is being developed. This efficiency is not a negative "short cut" as a rule, but rather the keystone to the success of the Design&Build model.
Rather than a parcelized level of responsibility of the classic design-bid-build, design-build provides an integrated entity to the owner or client. This moves projects away from the "finger-pointing" that is often commonplace in contemporary construction projects, and allows the owner to look to one entity with any questions or concerns. The client's risk exposure is different in the sense that all eggs are in one basket, so to speak. Replacing under-performing members of the team can be much more difficult than with traditional model.
Single source Edit
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.
Value-based project feedback Edit
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.
Almost 70% of traditional contracts end up over budget, compared to D&B which is only around 25-30% over budget.The overage of a D&B project is generally owner driven, whereas the overage in the more traditional method tends to be a result of the budget disconnect to which many architects and other design professionals are prone.It is also possible the D&B budgets are not as often exceeded because they are higher in the first place since much of the work may not be competitively bid.
- ↑  Design-Build Institute of America, Awards - Preston Haskell
- ↑ http://www.aia.org/pub_yaya_negotiating&grandCh=yes
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