Pathing requirements and preventions

[TotalEclipse]

Hey guys, I was wondering if you could help me. I'm trying to make a new maul called Hygine Maul (my first real attempt at a map, I have had experience, but never finished a map). You see i'm having trouble with setting it so you can build towers on shallow water or in other words amphibious land. But at the same time keeping the rule of not being able to build on rock, brick etc. Though I have already tried messing with pathing requirements and preventions. Any ideas?

 

[Demonspawn21]

You could use a trigger for this.

Pathing
    Events
        Unit - A unit Begins construction
    Conditions
        (Terrain type at (Position of (Constructing structure))) Equal to Lordaeron Summer - Rock
    Actions
        Unit - Explode (Constructing structure)

Of course i'm assuming you use TFT.

 

[TotalEclipse]

Thanks a lot Demonspawn21 it's helped me a lot, and yes I have got TFT