外墙防水工程在整个建筑工程中占有重要的地位。外墙防水工程涉及到建筑物（构筑物）的地下室外墙、住房外墙等诸多外墙结构，其功能就是要使建筑物或构筑物在设计耐久年限内，防止雨水、生活用水的渗漏和地下水的浸蚀，确保建筑结构、内部空间不受到污损，为人们提供一个舒适和安全的生活环境。
External wall waterproofing is a part of waterproofing project to ensure that the structure of buildings (structures) is not invaded by water and the internal space is not harmed by water. Exterior wall waterproof engineering plays an important role in the whole construction project. Exterior wall waterproof engineering involves many exterior wall structures of buildings (structures), such as basement exterior wall and housing exterior wall. Its function is to prevent the leakage of rainwater and domestic water and the erosion of groundwater within the design durability of buildings or structures, ensure that the building structure and internal space are not polluted, and provide a comfortable and safe living environment for people.