I managed to find some spare time to invest in finishing this long project. I started out airbrushing the entire building with consecutive layers of Shadow Grey, Fortress Grey, Skull White. I like Shadow Grey and think the combination has the right concrete look to it. After this job I airbrushed a rather astonishing amount of wash around burned out and bomb-shelled windows and other features (and where fancy took me). All I can say is long live Vallejo for supplying these huge barrels of wash (black and sepia for those keeping score).