: You can technically build while another player is moving, though common "gentleman's agreements" suggest waiting until a dice roll is completed.
: You must own all properties within a specific color group (a "monopoly") before you can build any houses on them. when can i buy a house in monopoly
: You can build between the turns of other players. : You can technically build while another player
: You must build houses one by one across the entire group. For example, you cannot have three houses on one property and only one on another in the same group; they must stay within one house of each other at all times. : You must build houses one by one across the entire group
The official Monopoly rules state that you can buy and erect houses " at any time ". This flexibility is often misunderstood, but as long as you meet specific property requirements, you don't even have to wait for your own turn to start building. Core Requirements for Buying Houses
: None of the properties in that color group can be mortgaged.