I want to take up an existing parquet floor which will no doubt crater the existing concrete surface underneath. I want to fill these craters without raising the overall level of the concrete. What product do I use?
When you say "crater" i'm guessing that you have a floor that is not absolute level. If that is so, you can buy a good self leveling compond from wickes. If you just need to repair holes in the floor a bit of limestone gravel no bigger 10/0mm and some grit sand mixed together with cement and water. Should be okay!
Best of Luck