A Columbia couple has pledged $500,000 to the Sandhills School, which will use the money to complete its new high school building.

Two of Tom and Gloria Faulds’ children graduated from the independent, college-prep school, which serves first- through 12th grades.

Michael Thacker, chairman of the board of trustees, said the generosity of the gift is “almost unheard of in a school as small as ours.”

Sandhills was founded in 1970 by 13 families who recognized that their children, while bright, were struggling in a traditional classroom setting. The school is on Hallbrook Drive, in southeast Columbia. It has 70 students.