I’ve been playing with matches, and I’ve found that the pile of wood a door gives you is enough to make a lethal fire, but not enough to cause it to spread. In practice, this makes deals with a hoard really simple, just lure them to a broken doorway, and a few turns before the first zed enters, light the pile. They all step in one at a time and burn up.
Unfortunately, I just lost my base by doing the same thing to a cleared out broken window with a stick on it, and the fire engulfed the entire house. Oops. I just don’t know what went wrong.
Anyway, this technique seems way too powerful, easily cleaning out a dozen zeds at a time if you’re careful. I think this should be nerfed. A burning zed should have its inventory torched, but it should be able to survive long enough to step through the fire, especially if it’s a small seconds old one. Burning zombies inside your base (or any enclosed space for that matter) should make the threat larger, not smaller.