Excerpted from Harvard Design Magazine, Spring/Summer 2010
Our practice is unusual—it is medium-sized; it does not have autonomous branches; the creative design is centralized in Boston. We have public and private clients in China, Singapore, India, Israel, Hungary, the U.S., and Canada. The nature of practicing, technology, and the construction industry varies greatly in these countries, yet we cope comfortably with this wide spectrum.
The tendency in North American practice is to try to define and detail a building completely before turning it over to a contractor. Then every time you want to adjust something during construction, there are change orders and extra costs. You can mitigate that by establishing up front that certain components or building elements will be undertaken in a “design/build” process. For the United States Institute of Peace building in Washington, we recognized that we could not detail the glass roof without knowing who would build it. Each of the companies specializing in glass 3-D structures has its own technologies and proprietary detailing methods, so the design drawings we presented them expressed intent only. We then paid three short-listed manufacturers to develop schemes with detailed drawings and costs. We chose the most promising (but not the least expensive) scheme, and then had life-size mockups built to fine-tune the design.
In Singapore, at Marina Bay Sands, working with a private developer and their powerful management team, we have been fine-tuning the design, working with most major subcontractors, and deploying mockups and other methods in collaboration with almost every trade. Roofs, cladding, glazing systems, structure, and lighting were all the outcome of this collaboration. Any attempt on our part to have drawn it all ahead of time and independently of contractors would have been impossible. The owners allowed us this flexibility through the way they set up their procurement structure. We respond opportunistically.
There is danger in this new situation that the contractor and owner might compromise the design intent by opting for a cheaper and weaker detail. In some situations, particularly in Asia, developers derail designs when suggestions are made in the name of “value engineering.” But the advantages of close work with contractors outweigh these dangers.
We much prefer having flexibility during construction; we enjoy it as a matter of course in India, Israel, and Singapore. In Israel, for example, the contractors bid in unit prices—so much per square foot for stone, for concrete, and so on, and then there is an accounting, so if we cancel a piece and add a wall, the overall price is adjusted without complex change orders.
The need for mockups
Our office makes all kinds of models in vast numbers and scales, but we cannot resolve a building with paper, 3-D studies, and physical models. Things come up—the way materials join, a new perception of color and texture, relationships of parts—that cannot be anticipated. In America, within the current bidding system, there is little room for this exploration. All we can do is ask the owner to set up a 2 to 4% contingency for change orders to allow us to make adjustments during construction.
We think that life-size mockups built by the contractors are essential. In Crystal Bridges Museum of American Art in Arkansas, we have mockups of the roof, skylights, wood beams, and cable structure: to test the behavior of light through the skylights, the meeting of materials, the waterproofing, etc. You have to devise contracts that include the mockups (sometimes mockups are built before the contractors are on board). Meanwhile you have to be careful to protect the owner’s financial interests by clearly stating design intent, asking bidders to give guaranteed maximum prices, then entering design development with the contractors. Sometimes this means going through several bidding steps.
The full article covers: the American construction management model, public/private turnkey construction process, urban design/ zoning, the authority of the profession, globalization, the expanded design team, sustainability and integrative building systems, and implications for architectural education. It is available as PDF below.