Sustainability goals include minimum reductions of 50% in energy use and 65% for heating and cooling, compared to existing use. Another goal is to reduce carbon dioxide emissions by a minimum of 45%, and reduce water use by 40%. The project is aiming for a LEED Gold certification—the second highest of four rankings—from the U.S. Green Building Council's green-building rating system.

The total cost of the GMP contracts is nearly $1.5 billion, including $140 million for a 190,000-sq-ft temporary building on the north lawn that is providing swing space for conferences and meetings.

The CMP attributes the 12% budget overrun to schedule and other costs linked to the security redesign, unforeseen conditions, complications of renovating partly occupied basement space, and project management and design cost increases. "We're not embarrassed by 12% over five years for a project [of this complexity]," says Adlerstein. The U.N. has been modifying scope to trim costs.

There are six main local design consultants. Architect-planner Perkins+Will (P+W) has the contract for programming, strategy, logistics and peer review. Syska Hennessy Group (SH), which designed the original U.N., is also the mechanical-electrical-plumbing engineer for the Secretariat. Einhorn Yaffee Prescott is the architect for the assembly building. HLW is the architect-structural engineer for the Secretariat and the temporary building. R.A. Heintges & Associates is both the curtain-wall consultant and curtain-wall architect for all the buildings.

Though each subproject has a different consultant, there are campus-wide contracts for all the new building systems: life safety, building management, security, heating and cooling, plumbing, telecommunications and electricity.

"Everything is feeding from one building into another," says John P. Gering, HLW's managing partner. "There are many interconnections."

The designers developed master standards and a master specification. Even so, there was a lot of difficult coordination among the various designers and contractors because the subprojects are phased and therefore not designed or rebuilt at the same time, says Daniel Kolakowski, a senior vice president with the renovation's construction manager, the local office of Skanska USA Building Inc.

Tortured Past

The renovation has a somewhat tortured past. The U.N. halted work on its initial full-blown master plan in 2005, when the New York state Legislature refused to pass enabling legislation to construct a nearby annex for swing space.

A year later, Louis Frederick Reuter IV—CMP's first executive director—resigned in frustration. His reasons included a lack of support by major U.N. stakeholders and difficulties working within U.N. practice, according to the international organization.