Spike Barricade is researched at the University. From levels 1-3, this technology adds 1 splash attack to each structure in the city per rank, excluding towers and cannon towers. (It does not stack in any way). This effectively increases the damage structures can do.

At level 4 Spike Barricade (University level 12) the splash damage for Towers and Cannon Towers increases by 1. This is the only level of Spike Barricade that affects tower damage. 


Official Database Entry