Answer: check that there is a vacuum.
Condensation is often synonymous with discomfort and humidity. It is formed when hot air is in contact with cold air. The greater the contact, the more the condensation problems will be, sometimes going as far as runoff. This phenomenon is most frequently encountered under the roof, because it is often the least well insulated place in a house. In winter, the cold outside air comes into contact with the often warmer roof, especially if it is not properly insulated. The origin of the problem is often linked to the absence of an air vacuum or to an insufficiently ventilated air vacuum between the insulating material and the plasterboard. It should then be checked that the roof includes ventilation grilles and that the insulation is not in direct contact with the plates. If that is not enough, you can strengthen your insulation from the outside or add ventilation under the roof. Our practical DIY videos