Carlos of Arco Iris gave us the best price (of five contractors) and result on replacing our very thin, root-heaved basement slab (after all planning was done on our part, a wise requirement to ensure clear specifications, done August 2006), adding Delta MS membrane, interior weeping tile and filling in over new main drain (different contractor). His cement finisher stayed most of the day to give a very smooth finish to the slab. He's now underpinning a friend's basement & prepping for a heated slab, and they're very happy with work so far (2/3's done).