Can I put carpet tiles over existing carpet?
Regarding this, can you put peel and stick carpet over carpet?
First, you should try to even out your existing carpet as much as possible. It helps if your existing carpet is low-pile as plywood is not that heavy. After putting the layer of plywood over your existing carpet, you can proceed to glue the pieces of carpet tiles according to your design or chosen pattern.
Similarly one may ask, what kind of flooring can you put over carpet?
You can also install laminate over existing floors made of wood, concrete, ceramic tile, vinyl sheet or even carpet. (Carpet must be fully adhered and no more than 1/4" thick over suspended wood subfloors.)
Old carpet can be used in lieu of new underlay when budget insists. Its not a perfect option, but its a lot better than no underlay, and I've not run into troubles using it. Used carpet doesn't yield as much as underlay when stepped on, but its far better than no underlay at all.