I was wondering if it would be possible to make a flag so that only wall and foundations are immune to damage. I like to make bases that are ment to be raided by other players with the reward of really good gear and resources, hoever a lot of them like to just blast through the side, as opposed to going through the doors and dealing with the traps I've set up. I'd like it so that things like Traps, Fences, Chest still take damage, but walls and foundations will remain untouched.

You can do this by adding the DamageControl plugin to your server. In the config file it lets you modify how much damage foundations, walls, doors, ceiling, etc take.