wow, first of all thanks for all the nice comments
Sir_Price, sure you can rent the top floor apartment and grow a roof garden, just don't water it too much as the cardboard support and paperback 'tar paper' might leak
It's made of 2 layers of 0.020" styrene strips, inner layer horizontal with 'bits' vertical, and outer layer vertical strips with 'bits' horizontal between the windows (does that make sense?). I did it this way because I thought it would be faster than cutting all the window openings in a sheet of 0.040" styrene, but I ended up spending a lot of time trying to hide/fill the small gaps that was created, so next time I will probably cut the openings and use 2 layer of 0.020" instead. One good thing though was that after I used the green putty for sealing the gaps, I sanded it with 220grit sandpaper (or was it 330, it is the finest one), and that's what gave it the kind of stucco texture.
belg, it's N scale and I used Micro Mark RTV for mold and their RS300 resin. I can try and take a picture of the 'original' window I used for the mold if it's not too tiny, but it's basically just build from 0.010" styrene and 0.020" x 0.040" for the frame.
As far as finishing touches goes, I haven't planned anything yet, but of course some window blinds, and some signs once I decide what kind of store it is, but for now I will just leave it as it is.
