Unfortunately, regular butter frosting does not work for a gingerbread house. It doesn't dry and the walls collapse. A good gingerbread house frosting should dry in ten seconds. You should be able to hold the pieces together with the frosting for ten seconds and then let go.
Frosting with a maximum of three ingredients works best -- meringue powder, egg whites and powdered sugar. You can add food coloring if you want. Don't even think about buttercream or cream cheese frosting, it's not going to hold.