I put in the rear wall section here (on the left side):
I also glued on the trimmings and concrete outside ledge. During the cutting I decided to up the breadth from 1 cm to 2 cm so I could position models on it. It looked bad, so I cut it back to 1 cm.
After the ledge I picked up a plastic L-profile at the local DIY-center and used this to give the corners of the building more character. Tomorrow I will have to pick up a second, broader profile to make the front of the building even more impressive.
Finishing this detail I found the courage to start 'destroying' my project to add battle damage. After that I made the insides of the Windows from wire mesh. It was a bit of an experiment that worked really well I guess:
To finish up, fix the Windows in position and make sure exposed bits of foam board won't start to melt as I ground the building I covered these bits with watered down PVA glue. Next time I do this, I will add a few drops of red paint to the PVA mix to make it easier to see where I have already been (and what better way to remind myself then writing it down).
And the this is where I am right now:
As I'm still not sure how to proceed with the concrete I decided to make a quick test piece and try out filler. This is the test piece. I applied the filler with a very, very bad (and very, very cheap) brush. This is the piece with filler, as soon as it is dry I'm going to try scouring it.
So far so good, until the next update.