I'm in the planning stages for building a small coop. The roof could be covered by a plywood sheet that is 4'x8'. If I just painted it, would that be enough to handle the rain and sun? We have mild weather here in northern California so I don't need to be concerned about snow. The roof would have a slight pitch so that rainwater shouldn't puddle on top. I've never shingled anything and I don't know if it's necessary to bother with learning about it for such a small project. Thanks in advance.