Question about Zombie persistence.

[Red-_-Monkey]

I've found myself a torch and welding mask and I'm eager to start biulding stronger fortifications, what I'm worried about tho is whether it'll be for nothing in terms of convenience. When I see zombies banging their heads on doors and windows, I cannot remember them ever giving up and moving along, so if I were to baricade a window with metal sheets, all a zombie would need is a bit of time in-order to break through. Do they ever give up or get distracted on their own accord?

Also, If I were to place barbed wire under that window, would that zombie take damage over time?

[print]

metal is a pretty solid upgrade