The Fairfax County School Board agreed last night to spend $1 million to buy and install 32 temporary classroom buildings to accommodate growth in the western part of the county.

At the same time, the board expressed concern that the purchase of some of those temporary structures is required because a county-funded day-care program is taking up classroom space that otherwise could be used by students.

The 32 temporary buildings are being purchased from Gelso Space for $584,800. The rest of the $1 million cost is to install the buildings and hook up utilities. The buildings will be available for use by the end of September, school officials said.

Most of the new structures will be used in the fast-growing western areas of the county. School staff estimate overall enrollment, now 125,000, will grow by 3,400 students next year. The purchase of the additional temporary buildings will bring the total number of temporary classroom buildings to 190.

As the board approved the purchase of the new temporary buildings, it asked Superintendent Robert R. Spillane to ask county officials for financial help on grounds that purchase of some of the buildings is being forced by the School Age Child Care program -- a county-funded day-care program run in the schools.

That program, which is so popular it has a waiting list of several hundred children, is housed in permanent buildings because the youngsters must be near bathrooms. Temporary buildings do not have plumbing.

Because the classrooms used for day care are in use for much of the school day, they cannot be used as regular classrooms. Thus, some School Board members said, the School Board must use money from its budget to buy temporary buildings made necessary by a county program that takes up school space.

Fairfax County is not the only area jurisdiction facing school overcrowding. In Alexandria, Superintendent Robert W. Peebles told the School Board Wednesday night that it should consider removing 175 pupils and adding two portable classrooms at Cora Kelly Magnet School to solve crowding there.

Alexandria School Board Chairman Lou Cook said she was optimistic that Peebles' plan will be adopted June 25.