Quote Originally Posted by PokeyTheNinja View Post
Never had issues? I have my tubs directly on the UTHs and in a rack I have set up there will be no ventilation per-say for the heat meats and heat tape. I've always heard it was okay to place tubs directly on top of the UTH as long as it's regulated correctly. Especially since I like to thoroughly clean my tubs, I don't like having to rip off tape and then secure it again.
Sorry to steer away from the original posters.
With heat tape it is, but heat tape and UTH are two different methods of offering heat. Heat encapsulation is a concern with the UTH. Which, annoying as it can be, can make or break an insurance claim should the UTH fail and cause a fire or burnt snakes. They include it in their booklet for most major brand UTH (ZooMed, etc). Ultratherm also mentions it on their materials (see bottom of page).

However, IIRC, having tubs constantly rubbing flush on heat tape can cause the laminate to wear through and the tape to fail.

Just something to consider with rack designs, or else plan for appropriate backups like smoke detectors. Another reason that the more-expensive proportional thermostats are all but necessary for racks, as is regular replacement of the heat tape every few years.