Analysis on the reasons for adopting exterior wall insulation in the buildings

    Ultra-low energy consumption and nearly zero energy consumption buildings can greatly improve energy saving efficiency and create a comfortable and healthy building environment for people, which has been widely concerned and actively promoted in the industry. The envelope structure of ultra-low energy consumption/near zero energy consumption building must have excellent thermal insulation system. At present, the form of external thermal insulation is mainly used to meet the corresponding energy saving requirements.

What are the advantages of exterior wall insulation system?

    The exterior wall insulation system can protect the main structure of the building from weathering and mechanical strength, and play a positive role in ensuring the stability of the building structure and prolonging the service life of the building. Similar to the principle of putting on warm clothes for the body to keep out the cold, the outer wall insulation structure provides a thermal insulation coat for buildings. Decades of successful engineering practice around the world has proved that the outer wall insulation technology has excellent stability and reliability.

    In fact, under the premise of using the same insulation materials and meeting the same building energy standards, the heat loss of external insulation is 5-30% less than that of internal insulation and the thickness is 20-60mm less. Especially for ultra-low energy consumption and near zero energy consumption buildings, exterior wall insulation system saves materials and has better insulation effect, which is a more scientific and reasonable structural form.

    The exterior wall thermal insulation structure can effectively eliminate the cold and hot bridge generated by the building floor, beams, columns, and the partition wall intersecting the external wall. Hot and cold bridge will not only cause the loss of energy consumption, but also prone to condensation due to the influence of heat and humidity, resulting in surface moisture and even water drip, leading to the growth of mold. While destroying interior decoration, it is very adverse to health. Therefore, ultra-low energy consumption and nearly zero energy consumption of building wall envelope are basically adopted in the form of external wall insulation, in order to avoid the problems caused by hot and cold Bridges.

    With the continuous improvement of building energy saving standards, the thickness of external insulation materials in the envelope also increases correspondingly. In ultra-low energy consumption and near zero energy consumption buildings, material thickness of 150-250mm has become normal. If the thickness of the insulation layer is adopted in the external wall, the thickness of the insulation material will increase to more than 200-300mm, which seriously encroachs the indoor use area and is a rather uneconomic approach for residents.

    At present, the state is vigorously promoting energy-saving transformation of existing buildings to reduce building energy consumption. If internal insulation is adopted in the existing building energy saving renovation project, temporary relocation of residents is required. And if the use of external wall insulation, during the construction of energy saving transformation, the work and life of residents will almost not be affected, indoor decoration, HVAC installation is not delayed, parallel operation can improve the overall building efficiency.

    The external insulation technology complies with the objective law of building development and its reliability has been verified by a large number of domestic and foreign engineering cases in decades. Under the background of active development of heat preservation and energy saving technology and promotion of green building in China, it is necessary to vigorously promote external thermal insulation technology.

    However, in recent years, some provinces and cities have issued policies and measures to prohibit or restrict external wall insulation, because of some quality accidents of external wall insulation projects in these areas. In fact, the main cause of the problems is usually the construction units using low-price inferior products, construction standards and quality supervision is not in place. Therefore, we should improve the responsibility mechanism, implement relevant policies and norms, really play the energy-saving role of external insulation technology, promote building energy conservation, and promote the realization of social sustainable development.