Sadly it is. I was going to remove it, but it is glued to the plywood(thanks previous owner).I know it's off topic, but are you saying that the floor of your grow room is carpet? If so, not a good idea. If not, sorry I misunderstood.
Carpet and mold/bacteria/insects go together like weed and the munchies.
My plan for that is to put the Mylar on the walls, then I have 3mil thick plastic I am going to put on the floor and staple to the sides and corners, to make a cup of sorts. My only concern there is friction for when I walk in there. I will have to be careful.
Basically the guy that owned this place before me built himself a office in the basement. It has ventilation, it is insulated, it is raised off the ground, and it has a door. I built three rooms in this area as my work area