Can you further explain the heat welding, and is it the best option when installing over commercial low-pile carpet? Does the double-stick tape method work when installing over carpet. We're looking at a 2200 sq ft room.

Over low pile carpet, using a heat weld is not the best option. Since heat welding is used in permanent installations where glue is necessary, it would be best if the carpet were removed. If you are installing over low pile commercial carpet, we would recommend installing the rolls with double sided tape.