The panels are laid between the logs of the frame of the first layer of insulation, slightly pressing them. But you should leave a small gap to ventilate the floor. When spreading the second layer of insulation, it should be fixed with rafters. The guideline must be kept on the intervals between neighboring beams, then you can cut the material correctly. The insulation when cutting should be wider, on all sides by about three centimeters, compared with the distances between the beams. If you want to turn the attic into an attic room, then a cork coating is perfect as a flooring. The cork flooring is not afraid of moisture, mechanical damage, serves for a long time, looks beautiful and is inexpensive.
The panel should be deployed from the side that is opposite the entrance. After that, the insulation is rolled throughout the attic. Sites through which cold air can penetrate are covered with material. Attention should be paid to the fact that thermal insulation does not go out beyond the upper edges of the beams. Excess must be cut off. If glass wool is used as thermal insulation, then a cut with rough incisors is perfect. If there is a cladding in the attic that performs protective actions from fumes, then the edge of the shield should be cut, cutting the material quickly onto the panels. As few should be joints as possible and this should be strive. You should not use trimming, it can only worsen thermal insulation properties and quality. Chimmers are isolated from contact with thermal insulation materials.
