The vapor barrier film has different parties in appearance and texture. One of them is smooth and the other rough. It is the rough side that must be placed on the insulation. The rough side delays the condensate drops formed at the dew point, since in any case there is residual moisture content of the insulation. Evapion can only be achieved when there is a ventilation gap between waterproofing and insulation. When installing thermal insulation, it is advisable to provide air gaps of three to five centimeters between the insulation and the waterproofing membrane. This will guarantee the greatest efficiency. It will not be superfluous to learn more about the repair of air conditioners at leisure on the Internet. A pressure difference appears in the ventilation gap and natural air circulation is created. Due to this, the residual humidity with pairs is removed from the insulation along with the air flow. Such a process will be impossible if the ventilation gap does not leave. To date, there are such waterproofing membranes, the vapor permeability of which allows you to perform installation without gaps, but such a question needs special attention. When laying, in no case violate the integrity of the vapor barrier film, because otherwise there will be not many benefits from it. If damaged places appear on it, swing them with a special tape.