Greetings! I am helping my girlfriend build some custom viv's for her snakes. They will be made from 1/2" plywood with a plexi sliding door in front. My idea was to use Flexwatt sealed under a layer of tile and grout - just like you'd do for a bathroom radiant floor. I see conflicting information online about this - the manufacturer says it must be "vented" or it will overheat... yet I've seen tons of setups with the stuff taped directly to the floor of a rack shelf - including youtube instructionals from companies who sell it. A few people have asked about putting it under grout but always get told that it needs to be vented / it is a bad idea. I don't get this. grout / tile is a way better conductor of heat than air - If overheating is an issue than laying it under tile seems like it work better. Other manufacturers have similar products that can be used under tile (warmzone.com, etc...) so it doesn't seem like a limitation of polyethylene film heating either... If it were my snake, I'd give it a go and see what happens... since this is for the lady I want to make sure it's right. Any ideas?