Hi folks, I will be having a wool carpet and synthetic felt/fiber pad installed over an existing ceramic tile floor, which is on a concrete slab. I'm not sure if this is a well known fact, but ceramic tile even today may contain lead in the glazing...the paint laws did not apply to tile since it is locked in a glaze. Obviously this becomes and issue if the tile is destroyed or sanded. I had mine tested and they do contain lead. Most do. But the methods used to install the carpet is a concern as I have small children. I'm having my carpet installed over this tile. The grout lines will also be skim coated to avoid any lines eventually telegraphing through. The installer said neither the glue down of the strips nor the skim coating would involve any kind of scuffing or sanding of the tile to try to improve adhesion, he said that's not necessary...which is good. He did say the tack strips, in addition to the glue, would be nailed at the grout lines. Is this necessary? Another installer had told me that he would glue only, no nails...but would come glue the strips one day, then install the next. The installer I am using says the job can be done in one day. My concern is that the grout lines are small and nailing may still chip the tile up which would potentially release lead. I'm using this installer because he is also a dealer for the carpet I selected, wanted to keep it all under one roof. Are most glues strong enough to be used on their own to hold down the tack strip and would I be reasonable in asking if nailing could be avoided? I read that some glues do allow you to stretch the carpet in on the same day. The tile is glazed but matte. Thanks for any advice! I absolutely hate telling a professional what to do regarding installation procedures...in this one case it's simply a matter of health/safety.