Hi I have concrete floors in my house and the kitchen at some point has been knocked into a kitchen diner. To that amends there is a prominent ridge/lump where the adjoining wall would have been?. I want to laminate the floor but obviously it is not level. How can I take this ridge/lump out or level the floor off so I can lay the laminate without it having a big lump/ridge in the middle. The ridge/lump is approximately 4 foot square (may have been a larder) but the remaining floor slopes off ok and I think I can work with it. Thanks for any advice.