Thermal bridges are places in the insulation layer where, due to reduced thermal insulation properties (caused by joints) heat loss is increased. Thermal bridges show up, for example, because of improper technology, improper assembly or poor adhesion of one material to another (eg, between rafters and traditional insulating material, or as a result of splinters or slipping down). The easiest way to observe the effects of thermal bridges is to set the window in the trickle ventilation position. Then you can feel how much cold air enters the room. Thermal bridges are also visible in the case of frozen rafters, which often produce black vertical stripes on gypsum-plated ceilings.