Firstly, if it Rained Houses, everyone will now one a new House, but it might get very difficult to get out of it!
Secondly, Houses are pretty heavy, if it Rained Houses, rain may now feel like an earthquake!
Thirdly, if it Rained Houses, even wild animals might give up their trees and start living in Houses!
Lastly, if it Rained Houses, as soon as they spot a big House, some people may pack up and shift to the new House!