What is the installation recommendation if you have a concrete floor that is not level? Can these be glued down?

Depending on how unevenly level your concrete subfloor is, you may have to fix the issue with a concrete leveling agent before installing the tiles. PAVIGYM's 6mm Performance Rubber Tiles can be installed over unevenly leveled subfloors, but if the tiles don't interlock properly, you can create tripping hazards across your floor. We don't recommend gluing the tiles, but you can. Since these are interlocking rubber tiles, they don't really need any glue to keep them in place. If you were to glue them, you would want to use one of our Polyurethane Adhesives.