WOW!, great job they look great! Are the pics you posted with the gray coat and the black drybrush already applied? . For distressing I use a sponge and slightly watered down paint. I would use black, green, and maybe a brown. Just soak the paint up with the sponge and squeeze it and let in drip from the top of your columns, then when the paint is almost dry get a damp sponge and try to wipe most of it off (drag the sponge downward along the drips) and this will create a remnant stain if you will. Check out my panel pic http://i709.photobucket.com/albums/w...HEKRYPT002.jpg....just to give you an idea. I would hit them with a watered down coat of black then bits of green and brown coming out of the crevices where your bricks are to look like mold. For the openings where the bricks are I would get your sponge and dab the brown or green paint around those openings, then whipe it downward after it dries for a little bit .I probably didn't make much sense but hope I could help.