If you want to add texture to your brick walls, here's a simple trick. Water down some wood glue (just a bit) and brush it onto your (popsicle stick) bricks. Get some Kleenex, separate the sheets (if it's two ply -lucky yo!u!) and lay it down gently over the bricks. Go back and get some more glue/water mix and then brush it on, it will give you the textures you see in photo #1.
Once that is dry you can basecoat in grey (add a little bit of brown and black to your grey) and brush it on, once that has dried just dry brush on some brick colours and you'll have something like looks like photo #3.
Photo #2 are the fire doors that I built, these can be easily made by cutting some up foam core board (you can get it at Dollarama/ Dollar Tree etc.) take some hard card or Bristol board and glue it down, I made the rest of the hardware out of some skinny dowel and coffee stirrers.
Find some shots of old bricks and you can end up with the bottom photo which is loosely based on the Soul Pepper Theatre Company rehearsal hall.
Don't forget to head to the Cameron House (in Toronto) to see my annual show of paintings