Window
Built into the side of a structure such as a house or other building, windows allow the player and zombies to see what is happening on the other side of the wall they are on.
Barricading a window adds 20 health and stops zombies from being able to see through them.
Single Pane Window
A small window with a single pane of glass. Most commonly found as windows in houses in the suburbs. The single pane window has 0.5 health.