KELLER - Just three years after it opened, Timber Creek High School is already overcrowded, and officials expect the school to be the district's largest by next year.The campus, located in the northwest corner of the district, now has 2,536 students, about 100 fewer than Keller High and more than Central and Fossil Ridge. According to the district's demographics consultant, the school could add more than 150 additional students next year and surpass 3,000 in four years.The building was constructed with a capacity of 2,500 because of budget challenges. A classroom wing that would have pushed maximum capacity closer to 3,000 was taken out of the project because material costs were skyrocketing during construction.At the Jan. 17 board meeting, trustees approved the first step in adding more classrooms at Timber Creek. Board members voted 6-1 to approve an architect for the 30-classroom addition.VLK Architects in Fort Worth, the original architecture firm on the $88 million campus, will complete the design work and help administrators determine the scope and cost of construction.Trustee Brad Schofield voted against the proposal because he wasn't sure that the best course of action would be to add on to Timber Creek. He asked officials to conduct a feasibility study to determine whether a fifth high school would be a better option. "I don't want to see Timber Creek become a giant high school," Schofield said.Demographic projections show total high school enrollment peaking at just under 11,000 in about 10 years.Superintendent Randy Reid said, "We may have to have an additional something for high school students but maybe not another comprehensive high school."Reid said that the school district likely would need to address renovations of older campuses in the next bond package and make efficient use of existing facilities, with more boundary changes a possibility in the future.Administrators expect the addition to cost about $9 million and would be covered by remaining funds in the 2008 bond package.Bob Templeton, the district's demographics consultant, said the Timber Creek feeder pattern has potential for more rapid growth in the near future.The Villages of Woodland Springs West had the district's highest number of annual starts over the last year. Future single family developments include 350 lots on property that used to be part of Christ's Haven Home for Children and 215 lots at Keller Hicks and Katy Road.Templeton said he expects the project on former Christ's Haven property to yield more than 220 students starting in late 2013 or early 2014. While a portion of the charity's property was sold for development, the children's home and its facilities still operate on about 150 acres off Keller Haslet Road.