An oxide is a chemical compound contaning at least one oxygen atom as well as at least one other elementMost of the Earth's crust consists of oxidesOxides result when elements are oxidized by oxygen in airCombustion of hydrocarbons affords the two principal oxides of carbon, carbon monoxide and carbon dioxideEven materials that are considered to be pure elements often contain a coating of oxidesFor example, aluminium foil has a thin skin of Al2O3 that protects the foil from further corrosion.
You don't want the foil vapor barrier anywhere but against the warm side of the entire insulation barrierIf it is insulated from the warm side, water vapor will condense on it, causing ice and water damage over timeIn theory, you could remove the vapor barrier and add a newly faced layer, or with an unfaced layer with a plastic sheeting covering it as a vapor barrier.
No, because the foil is a vapor barrierIf you add insulation on top you will gather moisture which will cause dripping and moldSon is in insulation business.
