This is how I create my 'sandstone' style urban rubble bases. While the pictured base is a mix of mud and stone it can be applied to more urbanised environments easily enough, just focus more on the stone sections and miss the mud parts where needed. Similarly the reverse is also true, if you want more mud than stone focus more on the mud aspect of the recipe. I use a mix of cork, slate and other bits to build out the base, as well as texture paints such as AKs Muddy Ground, or Citadels Stirland Mud. Other paints used include: Black Primer (AK Interactive) Chocolate 70.872 (Vallejo) Fur Brown (Army Painter ) Balor Brown (Citadel) Zandri Dust(Citadel) Ushabti Bone (Citadel) Skeleton Horde (Citadel) Contrast Medium (Citadel) Agrax Earthshade (Citadel) White 70-951 (Vallejo)