Choo Choo Charlie...
I usually plot a plan of a building on graph paper then transfer the dimensions to the Polystyrene and cut the pieces with a sharp utility knife. The Polystyrene is glued with Acrylic Solvent that welds it together. I use Evergreen StripStyrene for the trim, I used to make my own windows and doors but lately I have been buying them on line. When the building is finished I spray a primer on so I can paint it with Acrylic Paints. This building I used Rust-oleum multicolor textured spray paint , Desert Bisque and it gave the building a nice stucco look. The tile roof was bought on line. The foundation and steps are made from Precision Board. This building is a replica of a late 1800's NRA riffle association riffle range club house.