On terrains that include grass,You place a building and when you test it you see grass comming through the floor,All you have to do is place tiles where the building sits and like magic the grass is gone from the inside.
I found this out by covering a map im working on that uses a terrain with grass. I covered it With tiles to give it more of a green look,then when I tested the map where I put tiles the grass was gone.
Just thought I would share this.
