This is easy if you build up the morale in the area first and then take a heavier vehicle (garbage truck, dump truck, walkers, etc.) and just rush in, knock out the main supports to cause the building to collapse, and get back to a safehouse.
i hijacked a tank from the EDF and just ran into thier buildings then jumped out when the tank was going to explode and used a rocket launcher and other explosives.
lol nice i dident think of that i just ran in hammer and rifle and prayed for the best.