Idea: Havens
Not full-blown fortress building, merely being able to 'convert' a tile into a haven for your race. This would be most difficult for humans, whom would require building supplies that they must search for.
[spoiler=Human havens]Requires the building to be in full repair. Building extensions (functional only, I'm not expecting the map tiles to be re-drawn, only the description changed to note) that require nails, boards and other such materials or even tools to build. Towers and re-enforced doorway/windows; the ability to climb on to the roof and look outside without making yourself vulnerable. Makes it more difficult for undead to search and find you. Makes barricades take more damage to fall, or last longer when not maintained. Organisation can give a bonus to finding human-specific items.[/spoiler]
[spoiler=Zombie havens]Rapidly causes the building to fall into disrepair. Causes giant growths of fungi to take over the building, which makes it extremely difficult to find a hiding zombie. Possibly even heals the zombie a small amount per tick. The overgrowth makes it difficult for humans and vampires to traverse the building (2 AP to perform actions in except combat and conversion), and outright stops humans from passing through it via rooftop run (forcing them to go around the outside). The fungi causes the building to lose power by ruining the circuits.[/spoiler]
[spoiler=Vampire havens]Require the building to be destroyed. The building is decorated in gore, and everything inside and outside is smashed and broken, rendering the building's contents and functions un-salvageable (no items can be found, and other functions do not work, such as breakers which are locked to off). The gore has caused the building to be overtaken by pests and grime, making it extremely hard to see inside and therefore very difficult to find vampires hiding away in obscurity (also provides the only places blood-thirsting vampires can hide). The abundant rodents can be feasted upon to regain very small amounts of HP.[/spoiler]
[spoiler=Building conversion]Requires at least 2 participants of the same race inside the tile, and mass amounts of AP which is reduced by further participants. The buildings are converted in stages, or steps, with the bonuses and abilities slowly unlocked with progress. In order for a building to be converted from one creature haven to the other, the stages must be taken in reverse until the building is defaulted, and then continued in the desired direction.[/spoiler]
and other shit