Techniques/Tips for Modeling damaged concrete/buildings.

mrgesy

I have a project to beat up a model of a building to be swapped as a damage model. I'm having a very hard, consuming time cutting up the mesh to look like broken concrete and still not getting good results. The damage has to be modeled in the mesh without Zbrush. Does anyone have any tips for quickly breaking up models and surfaces? I tried adding noise to a plane and boolean on the mesh but it looks bad.