Whenever any school building or buildings have been rendered totally unfit for use by reason of fire, acts of God, obsolescence, overcrowding, inadequacy, or lack of facilities, or other unforeseen cause, the board of school directors of any school district shall have power to appropriate money out of the general fund of the school district to any nonprofit corporation established for the purpose of constructing school buildings for the use of the school district. Before any such money is paid over the corporation shall enter into a lease with the school district for the buildings proposed to be erected, whereby the school district shall have the right to renew such lease at stated periods at a stipulated rental and at any time during the continuance of the lease to purchase the buildings from the corporation at a stipulated price. None of the powers granted by this act¹ shall be used by the board of school directors of any school district without the specific and written approval of the Department of Public Instruction.²