Hello mattysupra. Please excuse the approach, but I am nearly ready to fit a Engineered wood flooring. Part of it covers existing floor board and one area covers 10ft x 10ft on concrete floor. I have been told to nail it at an angle through the toungue by some people other have told me to glue it. (they say it stops the wood spliting) I am still at a lose on how to fix it to the concrete flooring. The origanal floor board are with your 2/3 mm defiance over the area. I look forward to your reply. Many Thanks Ian (I note your Solihull I live in Nuneaton about 15 minutes away)