In 2009, when a request for proposals to design two dormitory buildings at Pennsylvania’s Haverford College—the school’s first new dorms since 1968—made its way to Tod Williams and Billie Tsien, the architects were reluctant at first to take on the project.

The New York firm that bears their names was in the throes of designing a new home for the Barnes Foundation, some nine miles southeast of Haverford, in Center City Philadelphia, and the duo felt they were overcommitted. But they agreed to visit the college as a courtesy and were charmed both by the natural beauty of the lushly wooded campus—a 216-acre, nationally recognized arboretum—and by Haverford’s Quaker tradition of treating its students as adults and giving them a say in major decisions about the school’s direction.

It was also clear from the outset that the college had no interest in building cinder-block bunkers of the sort that have become synonymous with campus living. Tsien and Williams say they responded to the school’s desire for new structures that would be architecturally daring without drawing attention to themselves.

“Tod and Billie had a vision that we thought was just extraordinary,” says Jim Friedman, who was chairman of the property committee of Haverford’s Board of Managers when their proposal was chosen. “They didn’t just design a building. They designed a site in which these buildings would blend into the landscape without making a statement; they would actually disappear below the tree canopy and basically go away.”

Kim and Tritton Halls, nestled into a gently sloping site at the south end of campus, opened in time for the start of the fall 2012 semester. The buildings are the product of a bold design vision, as well as clever responses to a series of unexpected challenges, the first of which presented itself early on when the students on the design committee insisted the buildings be composed exclusively of single rooms, rather than the mix of doubles and triples included in the architects’ initial study for the project.

“We had imagined that there would be many fewer rooms, and then when the students got involved, they made it totally clear that they didn’t want to share a room with anybody,” Tsien says. “So, suddenly, the number of rooms kind of exploded, and that’s when we really had to think about how to make the most with what we had.”

Tsien, Williams, and their team also quickly realized that the site was largely composed of unusable fill and that the soil had to be remediated. Spinning this into a design opportunity, Williams and Tsien used excess soil from the site to sculpt a berm that serves as a transit point between the two buildings. Stairways and ramps were carved into and around the berm, joining concrete-and-etched-glass bridges that provide direct access to the second floor of each structure—moves that allowed the architects to design the buildings without elevators or interior stairs.

Dispensing with these space-consuming elements meant that students would have to venture outdoors to visit friends on another floor of the same building. But it also enabled Tsien and Williams to expand the interior common spaces in the identical 21,500-square-foot structures. By arranging the rooms along the perimeter of each building—a courtyard, bathrooms, and common areas are in the center—they managed to comfortably accommodate 40 single rooms on each of four floors, for a total of 160.

Yet the buildings’ innovative design nearly proved their undoing, when some students and administrators objected strongly to the plans. “They said the things you would expect them to say if they hadn’t thought it through, like, ‘You mean we have to go outside to see the people who live below us?’” Friedman says. “It was upsetting, and it was somewhat controversial, but we just stayed with it, and we convinced them in public meetings. When you start getting your head around it, it made perfect sense.”

In part by reusing soil to create the berm, the architects found wiggle room in the $19.3 million budget to splurge on some materials, notably hand-formed Danish bricks and custom oak furniture. Williams and Tsien’s firm designed the beds, desks, and storage units, building a full-scale mockup of a room, on campus, and inviting students to tinker with different configurations and give feedback.

“We wanted the buildings to be lower than the trees,” Williams says, assessing the finished project. “We wanted them to feel as if they belonged in the land and of the land, and that they were part of the arboretum ethic.”

Friedman says Williams and Tsien succeeded by that measure and even exceeded his expectations. “I think it’s a truly remarkable, modest building,” he says. “So much attention is paid to immodest buildings that it’s nice to see this one get some recognition.”