Housing officials said the problem was caused by last-minute applications.
"We had more students than we anticipated, and fortunately we were able to open Spencer," said Christopher Payne, director of housing and residential Education.
"We took a proactive and responsive approach to that need," he said.
"The number of students who needed housing for summer and didn't have a housing assignment wasn't known to us until very late in the assignment process."
Summer housing assignments are made on a first-come, first-serve basis, according to the housing application.
The recommended deadline for applications was two weeks before the halls opened for summer session on May 21, but Rebecca Casey, assistant director for marketing and conference services, said applications are accepted throughout the summer until all spaces are filled.
Casey said there are usually more spaces available than are needed. She said allocations this summer were based on the number of applications for last year.
But according to housing records, last year there were 750 housing applications for first session. Casey said there were 741 applications this year, including 28 students who had applied after May 21.
She said these students were assigned to Spencer after it was opened to meet the additional demand from these last-minute applicants.