I assumed the same thing that a insulation foam sheet might be beneficial. But wasn't sure and kind of forgot that I wanted to do that.
My tent sits on the bare floor. We use to have carpet but it got old and smelly so ripped it out.
Now there is what I believe to be asbestos tiles and that is what my tent sits on. Also my tent bottom liner when I slide a pot and saucer one day it ripped a small hole in the tent liner. I can't find a replacement liner, and I'm not about to buy a brand new tent before I get the full use out of this one. I could patch the hole, but meh, my plants don't flood the tent too often unless I make a mistake, I just use a saucer for every pot. But yeah, I was also thinking if i go with the insulation foam board that stuff is also built with a reflective layer so that might help reflect some light upward too is its inside the tent.