Im tired of waiting to start the co-op so I moved on for now and planted the seeds for the coaling tower. I decided the best way to make it look like concrete is to cast it out of plaster. This is a first for me but it seems to be moving okay. I reinforced the plaster in the same way you would concrete. I used strips of plastic styrene as re-bar and it worked well. So until I have more done.
The prototype
The first cast sections