I tried this out to make guest slippers. It took a bit of work through trial and error. The real problem is that thick felt like that is really expensive and the thinner stuff doesn't hold a shape as well
Genius slipper design where you knit a short "scarf", fold and sew onto your bottom. Garter stitch extra chunky yarn about wide, and however many rows you need, then sew into the 2 layers of the felt bottom.