What do you need to build a skate ramp?

It depends on what you want to build.. concrete, wooden, or metal.. I'll assume that you are speaking of a wooden ramp.. You'll need 2 x 4's or longer.. you'll need plywood and then another material that goes on top of the plys, masonite, or skate lite. If it's an outdoor ramp use skate lite, if it's an indoor use masonite.