Waterproof and breathable system for outer wall

The utility model relates to the technical field of outer wall waterproof construction, in particular to an outer wall waterproof and vapor-permeable system which comprises a wall body, a heat preservation layer, a plastering layer, a vapor-permeable waterproof layer and a facing layer which are sequentially arranged from the indoor to the outdoor. The wet flow density of the vapor-permeable waterproof coating is 0.85-35 g/(m < 2 > h), and the thickness of the vapor-permeable waterproof layer is 0.2-2.0 mm. The vapor-permeable waterproof layer is arranged outside the wall insulation board, vapor water can penetrate through the vapor-permeable waterproof layer, but liquid water can be prevented from penetrating through the vapor-permeable waterproof layer, the contradiction that the waterproof capacity and the water vapor transmission rate cannot be balanced in an external wall insulation system is solved, an external wall has real breathing and drying capacity, and the service life of the external wall is pro