I moved the post to one thread
are you measuring the temp of the mat or the air in the cage?
heating pads work when the animal sits on it, but are rather ineffective for heating the whole cage.
and you are right, putting it under a wood floor will not work, the wood will block the heat.
some folks will place a slate tile over the heat mat, that way the slate heats up (kinda like a heat rock) and keep the animal from laying directly on the heater.