Therefore, generally speaking, external wall insulation is more recommended, such as the classic textbook "Architectural Physics" by Liu Xiaotu of China Architectural Engineering Publishing House. External thermal insulation is indeed adopted in some thermal insulation reconstruction in North China, and the construction will not affect indoor use and internal decoration of walls. However, when I was an undergraduate, I heard an academic report from our dean (Professor Qian in the direction of building materials).
There may be a fire hazard in the external thermal insulation of the external wall (the fire incident of CCTV building a few years ago). Some studies, including his own related topics, have proved that the internal thermal insulation is actually more suitable for some special areas (such as the middle and lower reaches of the Yangtze River, which is hot in summer and cold in winter) if the construction technology is proper and dew is avoided.
The latest technology is a comprehensive internal and external insulation, which has advantages and avoids obvious defects. If you are interested, you can learn about the relevant situation. Thermal insulation is not done because the concrete wall is completely insulated, but because the thermal conductivity of concrete is high and the thermal insulation effect is poor. The internal insulation system keeps the internal insulation of the wall, and concrete can easily transfer external heat to the internal insulation.
Due to the temperature difference between indoor and outdoor, it is easy to condense on the wall before heat preservation. After a long time, water will penetrate into the inner wall through the internal insulation, resulting in water leakage, mildew, peeling and falling off. On the contrary, the external insulation system can isolate the walls and rooms from the outside world, and keep the heat out of the insulation layer, which is not suitable for condensation.
Moreover, the external thermal insulation system is a hydrophobic and breathable system, which can also block some water seepage and expose internal moisture. External insulation, internal insulation and interlayer insulation can all be qualified ... but there are basic similarities between them. First, the insulation layer must be laid continuously.
Second, the external insulation of the main structure must reach ... To put it bluntly, these three forms of insulation belong to interlayer insulation ... The external insulation is actually the interlayer insulation with thinner outer protective layer; Inner insulation is actually interlayer insulation, and the outer protective layer is very thick and much thinner. The outer protective layer is connected to the main structure, and the inner protective layer is connected to the outer protective layer. Interlayer insulation means that the outer protective layer is connected with the inner protective layer, and the inner protective layer is either connected with the main structure or the main structure ... The outer thermal insulation and interlayer thermal insulation are actually the same thing ... The difference between the inner thermal insulation and the two is that the outer protective layer is too thick and heavy, and its connection points with the main structure are few and large, so the thermal bridge problem is more serious.