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1. Air circulation insulation method. It is to cover a hollow sandwich of about 30cm on the roof. When the summer sun is exposed, the flowing air below can effectively block the heat transfer effect. 2. Water insulation method. This method has high requirements on the quality of the roof. Now many residents use this insulation method. The roof is usually a shallow puddle, about 15 cm deep. This roof insulation method can be used to reasonably reduce the indoor temperature and is relatively simple.