Heating home-made wooden display cages

I've been thinking on this for some time. Haven't built anything yet, but thought I'd bounce the idea off y'all to see if there are problems I haven't thought of yet. Heating racks is easy. Most use FlexWatt or THG heat tape under the tubs, and have no problems, but heat does not flow through wood very well, and many say the heat tape might not be safe inside the enclosure. How about this: Cut cheap porcelain tiles in half so you have two 6"x12" pieces, then sandwich a 10" or 11" length of properly wired heat tape between them. Use a bead of silicone around the edges so it's nice and watertight, and maybe a dab of epoxy on the cord to make it secure. So, essentially, you have a nice, thin hot-rock. Anyone see any problems with this?

When I build mine I mortice an area to receive flex-watt and on top of that added plexi glass. I had a router to do the tho.

I was thinking of using porcelain tiles like you but thought to myself how hot dose the flex-watt need to get to heat the tile to the top ?

I would think that porcelain tile would transmit heat as easily as glass, and might be cheaper, too. Do you seal it in someway, in case water is spilled? Why do you have it recessed? I would think that might just collect moisture, unless it was sealed. Do you use some kind of substrate, or just newspaper? Have you had any other issues? I am just trying to learn from other's experience before I start to build my own. Thanks!

You could be right about that ... or not.
I just know wall tile is about 3/8" thick so that what I'm coming from.
But folks have done it that way with no problem.
I have it recessed so its flush with the floor and I seal it with silicone .
And I use aspen. It going strong with no problem