Painting the siding is a lark to do. Use a power washer and get the special cleaner from the local box store for prepainting. There's a dip tube from the washer that goes into that jug of cleaner and sucks it out as you wash the wall. There's directions on the bottle for this. I believe it's in the paint isle. May also be in the power wash products isle. It cleans the old chalk off very well and etches the paint for adhesion. I believe the paint we used ws an alkyd enamel. Might be wrong on that, but you can talk to the paint people at the desk and they'll steer you in the right direction. You'll need an airless sprayer to apply it. We did ours ten years ago and it still looks new. As for painting the brick, and, for that matter, the stone, I would power wash that, too. Use a spray pattern that covers about a brick height at a time and go slow without concentrating too much on the mortar joints. That sprayer is able to drill that mortar! Eye and ear protection is must. Face protection is best. A hot day to do this spay stuff on is great, too! You'll see that brick and stone in a whole new light when it's cleaned! You copuld then paint it. Don't see why paint on stome wouldn't work. Graffitti seems to hold up a long time on some of the buildings I've seen! And that's WITHOUT prepping!
