Basically the Insula is the "house" for the Principate Romans. It cost 250 and 100 , and gives 25 . It covers 2x as much ground as a Republican Roman house, being 2 Republican Roman houses wide (but same depth, so the footprint is a rectangle). Here, show the footprint: The 2 story part of Market looks very mich like how a Insula can look. Here is great reference: Need at least 3 variation.