My wife and I will be building a new home in southeast Oklahoma latter this year (and I mean we will be building it except for this few time I'll have to subcontract) and the issue of insulation came up. We both agreed to spray foam insulation (closed cell) for the exterior walls but she wants to envelop the whole house (spraying the rafter area as well). Now she read on the internet where once we do that the ceiling does't need to be insulated. But then the question of venting the attic came up. So my question is 1) Do we insulate the ceiling and 2) if we spray the rafter area should we vent or is it not necessary? We will have an air-exchanger for the house for those days when the house is closed up.