北方寒冷地区,屋面保温层的习惯做法是用1:10水泥珍珠岩做保温材料。其上做找平层,最后做防水层。这种做法,在拌合水泥珍珠岩时,需要加很多水。这些水,在施工过程中挥发掉一部分,但是,做完防水层后仍然有相当一部分水留在保温层内。这些水份在日光照射下变成大量水蒸气向外蒸发,因此,防水层极易产生 In northern cold regions, the practice of roof insulation is to use 1:10 cement perlite as insulation material. Do a leveling layer on it and finally make a waterproof layer. This practice requires adding a lot of water when mixing cement perlite. The water evaporates during the construction process. However, after the waterproof layer is still in place, a considerable part of the water remains in the insulating layer. These waters become a large amount of water vapor under sunlight and evaporate outwards. Therefore, the waterproof layer is easy to produce.