Outside, two men with chain saws were pulling the building apart from their perch in a metal basket hanging from a crane. The back of what looked like a tin ceiling could be seen around the edges of piles of wood and debris. Anthony Martucci, the owner of the demolition company, Tucci Equipment, said the debris would be separated as the building was taken apart, and what could be salvaged would be recycled or sold to antiques dealers. While the block is not a landmark, zoning restrictions dictate that whatever goes up in the building's place cannot be more than 50 feet tall. Ms. Schneider said they would build a home that fit in with the neighborhood. The cause of the collapse is under investigation, but Mr. Lynch said last week that one possible factor was the empty space next to the wall that came down. Nineteenth-century town houses, he explained, were generally built in clusters of three or four homes called sister houses, and the adjoining structures were a central part of what kept them standing. While the brownstone to the left of 241 Carroll Street still stands, the one to its right was torn down in the mid-1950s to make way for the school, Public School 58. Over time, very slowly, the lonely brownstone without its right-hand neighbor might have become unstable. "It's closing in on 200 years old, so it has performance issues like the rest of us," Mr. Lynch said. You've got to remember, Napoleon wasn't dead that long when they built this thing. Generally, Mr. Lynch explained, there are telltale signs before a major collapse, like cracks in the walls, buckling floors, or stairs coming out of alignment. But they are sometimes subtle, hidden deep in the walls, and it can take an engineer examining the brick to find them. The Schneiders said they saw no signs of disaster. Like most homeowners, Mr. Lynch said, they did not have the professional expertise to know there was a problem - Mr. Schneider works in computers, and his wife is a lawyer. By the end of last week, Mr. Lynch and the members of the demolition team had recovered many of the possessions of the residents, including family jewelry, computers, toys and clothing. "Mom, I have my ballet bag!" said Marion Floc'h-Barral, who lived in the building with her husband and their three children, recalling her daughter's excitement. The outfit is missing, but it's O.K. The only thing Mr. Schneider asked for was a cigar that he had left out on the counter on Sunday, figuring that with the humidity in the air, it would make a great smoke on Monday. Even Ms. Schneider sounded calm, though drained, when reached by telephone one evening last week. What can you do? It's the best-case scenario," she said. And if we walk away with 10 percent of what we had, it's still more than most people do. Her 15-year-old son, she added, had kept his life savings at home in a cigar box, and they were certain it was gone. But it was returned to them last week, and the money was all there. When something like that happens, she said, "you can't complain."