Gates

[Bakar]

I've made the same suggestion a while back, basically larger doors that take longer to open and close, much more durable than normal door and much bigger (3-5 times larger) the fact that it takes longer to open and close would make running away from raiders into a gated community and give yourself time to prepare to fight back more feasible.

Just really big doors.

[Nix_dot]

This sounds like an epic idea. Imagining it could be great as well for in base defense. But did you have "folding" or "sliding" gates?
Another downside to balance it could be an area of denial for swinging doors.