Sources masked and placed. some lighting and shading effects created with brushes. In the post process these light effects were dodged and burned.
step 2 of 4
background added. Each piece or layer has layer adjustments for photo filter and levels clipped to them.
step 3 of 4
The writing for walls made with some freehand brush work and fonts from Dafont.com (sickness, hardcore pen, rat infested mailbox) These were tweaked some with warp and smudge.