Ola Cartridge
For all my buildings, walls, leveling of debris, , mounts, Dio bases whatever I use Styrofoam. It`s a blue type of foam with a very big density. Every detail you can scribe in with a pen ( like bricks, cracks and such stuff) Really great stuff.
I have here a link to an article here on this site that goes aboutt the whole story of my winter diorama campaign dio that I did here hope it is of some help.
Disrtaction step by step Hope it is of some help but the Foam is really the ideal stuff to make such things.