We just got a house built here in Indiana and we went with sod for both the front and back yard instead of seeding. What has happened is in a spot in our front yard (probably 8X8 or 10X10) it is extremely low and retains water badly. It has basically killed the grass in this area.

Well the builder (a good friend of mine) said that they would fix it. The guy he got the sod from says dirt needs to be put down to raise the spot up (obviously) and you can just put the sod over the dirt without taking the original dead sod out.

Now, I do not know much about grass, but I would think the original sod would need to come out. Am I wrong in thinking this?