Did you even see a house being moved? I have seen houses moved on trucks, but have wondered how they lift them off their foundations. That is where I learned about screw jacks. Screw Jacks are basically meant to lift heavy objects, such as houses. large machinery and vehicles. Also I learned that you can by screw jacks online. Can you think of industries that may use jack screws? I was thinking that shipyards would have a need for them. Screw Jacks can support very heavy weights, so I would feel perfectly safe walking under any thing properly supported by a screw jack.