You destroy a house using a variety of different ways. You can strike a house with lighting, use a atom bomb. air strikes, flame throwers and all sorts of other ways. You could keep destroying the house until you got to a new level where you destroy different houses and unlock more weapons to use to destroy the house. As you destroy more houses the houses get more security. At the last level it will be like attacking a fortress. The fortress will be armed with anti aircraft guns, and other defensive measures and forces.