The brown stains leaking under the window sill are decals. The blue paint paint coming off the brick and the patches of damage around the windows on the top floor is probably a vertex blended material.
It's based off of this concept: Good point about the poles coming out of the water. @ Mr.Cash Thanks, when I'm done there is going to be water stains, scuff marks, and bird shit everywhere. :)
Image updated above, I added a normal map worble to the cookies, tweaked the glass a bit and added some staining where the icing meets the dough was looking a bit too cg.
Quick update on my wall tile. I pushed the random tilt of the tiles up a bit and also upped the color and gloss value of the water stains to help them read better