Hello, I an thinking of having Cortec Plus installed in my father's house in a basement. During the last hurricane we had flooding. They say the water came through the walls. Will the water get under the tiles?

The interlock on the planks is very tight, but it is not impossible that water could get under around the perimeter of the floor. Coretec is 100% waterproof, so there shouldn't be any damage to the planks. You would want to pull them up and clean beneath so that water doesn't sit there.