They're not really made of rubber, of course. They are big, empty rooms where they store the teachers they are afraid to let near the kids. The teachers go there and sit, hang around, read magazines, and waste time. The city pays $20 million a year to house teachers in rubber rooms.
A new union contract is supposed to make it easier to fire teachers for sexual infractions, but the Byzantine rules for other offenses remain. Insane as most are, some teachers told me they support the firing rules. "You prove I'm a bad teacher!" said one. "And if you can't prove it, don't try it!"
The restrictions on firing teachers are defended as a means of protecting teachers from favoritism. But if schools and principals had to compete, good teachers would be protected by competition itself: If a principal's job depends on having good people working for him, he won't sacrifice it to give a favored incompetent a job he can't do.
Taking six years to fire a teacher doesn't do anyone any good -- except bad teachers. So why do it? The short answer is unions. The long answer is next week's column.