Linthicum Elementary fifth-graders filed and sifted Monday into their classrooms, "quads" partitioned off by bookshelves and other makeshift barriers.

It is an image that is rapidly becoming a thing of the past, as county schools are spending millions of dollars on renovations to wall-in the classrooms at Linthicum and other schools around the county.

Teachers at the school seemed split on the issue.

"I like having it. If I need another teacher quickly I can just pop my head in," said Jennifer Crawford, a third-grade teacher.

But fifth-grade teacher Melissa Meikrantz sees clear...