Owners Guide to the Design and Construction Process – part 5 Design/Build Method
Friday, May 9th, 2014
The Design/Build Method: A Single Source Approach
The essence of the design/build concept is the idea that quality, completion dates, and costs can be brought firmly under control by assigning total responsibility for all these factors to one single entity: the design/build contractor.
Like the “master builders” of ancient times, the design/builder’s responsibilities span the entire building process, from conception through move in. To be effective, a design/build organization must combine strong management ability with experience in balancing good design with construction economy. We’ve been design/building long before it was even a buzz word, beginning in the early 1980s.
In the design/build approach, the contractor participates with the Owner in the conception of the project. The contractor has designs, working drawings, and specifications prepared, and then constructs the facility—all under a “single-source” responsibility contract.
As the design/builder learns about the Owner’s expectations and requirements with regard to size, function, quality, timing, and cost, he develops a building performance specification which includes a guaranteed maximum cost (GMAX).
All these expectations and requirements are closely interrelated. For example, function affects quality. A cost decision involving choice of materials can affect the completion date. An integral feature of the design/build method is that all these important factors are continually balanced during the development of the program, preparation of the working plans and specs, and even during the actual construction.
Value/Cost/Time studies are reviewed constantly during the planning stage, thus developing a practical solution consistent with project goals for function, quality, time, and costs.
In the conceptual and development phase, the design/builder conducts feasibility discussions. The project’s overall viability can thus be tested via various financial and spatial criteria. Through analysis of these, the design/builder and the Owner develop a list of specifications and a set of performance criteria that form the heart of the architectural program, and a GMAX is established.
It is essential that there be good communication and understanding at this phase, for these preliminary plans and definitions set the tone for the working drawings and establish the scope of work which is the basis for the guaranteed maximum costs. The Owner must insist on as much detail as he requires to feel his goals and needs are satisfied. Without this attention by the Owner, design/build can have problems which result not only in strained relationships, but a building that fails to meet the Owner’s expectations.
During preparation of the plans and specifications, costs are continuously monitored to make certain the GMAX will not be exceeded. “Long-lead” materials and equipment that may affect schedules are identified and ordered. If necessary, the project can be accelerated (fast tracked) by starting construction while the drawings are still being completed. This requires proper programming of the drawing production, phasing of the necessary permits, and ordering of long lead items for construction.
Ambiguities, misunderstandings, and confusion during construction buy-outs and execution are eliminated via fully descriptive drawings and contract documents outlining the level of detail acceptable to all parties. The Owner is made privy to the subcontractor bidding process on a full disclosure basis.
The design/builder should not be expected to control the architects or engineers in a way that inhibits proper exercise of their professional capabilities. The architect is contractually responsible to the design/builder, which permits control of schedule and budget by the entity responsible for completion and costs. Ideally the architect should not be an employee of the design/builder on large projects, since maintenance of his independent viewpoint is extremely valuable to all concerned.
For the Owner with in-house engineering personnel, design/build frees these people to work in their own areas of greatest competence, i.e., proper planning of the processes that the structure will house. Common contract forms and basis for payment are discussed in some depth later in this text, but it’s worth pointing out now that the procedure for developing the guaranteed maximum cost makes the GMAX, by its very nature, a negotiated sum.
The “bidding” disadvantages are eliminated, but the advantages are retained. The Owner and design/builder work together on a “cost-plus” basis, materials and subcontracted work are bid out competitively, and all costs are fully disclosed.
The advantages of negotiating a GMAX instead of leaving costs to the vagaries of the traditional bidding process are numerous. In the first place, costs are established at the beginning of the project and controlled thence forward. Ambiguities in the working drawings and specifications become the responsibility of the design/builder, as do cost overruns. Costs over the GMAX comes directly out of his profits.
You might think the design/build contractor would therefore attempt to protect himself by incorporating a healthy amount of “fat” in his GMAX. The answer is that this will work against him in the long run. Because of uncontrollable factors, such as weather, labor, and inflation, a prudent builder may include an amount of “contingency” in the GMAX, but proper contractual arrangements will protect the Owner by keeping this contingency sum reasonable. (See the section on contracts and payments.)
Summary of the Design-Build Method
At first glance, design/build seems to be an easy “one stop shopping” alternative that is ideal from the Owner’s standpoint. He deals with a single, responsible entity, has maximum freedom in selecting an architectural concept, is assured of quality commensurate with his intentions, and proceeds with the comforts of costs and schedule guarantees.
However, some Owners may perceive a disadvantage in that they lose a certain amount of their traditional direct control. The architects, engineers, and other professionals involved have their contracts with the builder instead of with the Owner. An Owner who feels competent to deal directly with the people in these disciplines may prefer the “team method” discussed next.