Ingame Description Edit
"Stronger quality. Gates open and close automatically to allow friendly units to pass through the walls."
General Discussion Edit
Gates are useful for partitioning your settlement into smaller areas, while still allowing you to transfer units between them. If a small portion of your settlement is overrun, interior partitions allow you to contain the infection and defend against it. Likewise, an exterior gate allows units to rally forth to attack infected, but easily retreat to a protected position if they draw more attention than they can handle.
Because of their large size and therefore attacking surface, they have much less resistance to attacks than stone walls despite their higher HP. Therefore they shouldn't be built directly in the line of the attack of infected, but rather sheltered behind a screen of other defenses. They are also more expensive than walls, and so they should only be used when they provide real value. Early on when infected hordes are small and the direction attacks will come from somewhere predictable, you can usually rely on the mindless infected to not be able to negotiate a complex path through your walls, allowing you to avoid the expense of gates until they are truly necessary.
They can be built directly or upgraded from Wood Gates.