University at Buffalo undergraduate Mindy Underhill straddles a ceiling beam, checking the joists in a home going up on Buffalo's East Side. Underhill, a junior speech and hearing science major from Marilla, N.Y., is one of a team of young women working on what they call "the girls' house." It is one of four new homes being built this year by Habitat for Humanity with major assistance from 36 UB students, and it is the 41st such house since 1990.