Roof insulation is generally how to do.

1, external insulation - the insulation material will be glued to the outside of the building, similar to the "wear cotton jacket". 2, internal insulation - and above the opposite, the insulation material will be glued to the inside of the room, such as cold storage practices. 3, sandwich insulation - a mature practice in Europe, when the combination of walls are rigid panels on both sides, the middle of the sandwich insulation material. For example, the practice of cold storage. 3, sandwich insulation - a mature practice in Europe, in the combination of walls, both sides are rigid panels, sandwiched between the insulation material. This method should not be thought of. Specific recommendations: usually we pay more attention to the top of the heat, in fact, the wall is also a heat source, although the absolute temperature is to be lower than the ceiling, but the area of the wall is almost 2 times the ceiling, so the heat emitted / absorbed will only be more than the ceiling. Adding extra insulation to the roof is not possible, only in the home idea, which is internal insulation. You can stick 5cm thick polystyrene board (that's foam board) to the ceiling, then stick mesh cloth to reinforce it, and fan the plaster and it's basically the same as the original ceiling, just 5-6cm lower. If the room is large enough, do not care about the use of a smaller area, you can consider even the wall with the same method of insulation. Theoretically, you can save 60% of energy consumption. But the room use area will be reduced by about 5%. With reference to the price of external wall insulation in the north, it is estimated that the price per square meter of the package price between 50-80 yuan (including interior wall latex paint).