BTW... There are some neat how-to's on YouTube, etc., if you search Foam Core Modeling.
One such shows the basics of building an architectural model....in which he uses Foamwerks tools...
...which are really cool, well thought out, if you're going to do a lot of this sort of building.
And, here's another interesting site that focuses on this modeling material...
FWIW, of course...
"Lucas Gudinov"