Air/Vapor Liquid Moisture Barriers: 

Air and vapor barrier membranes are an important part of the overall waterproofing and energy efficiency of a building. These membranes are designed to block air and moisture from entering the building's envelope. They work by creating a barrier that stops air and water vapor from seeping through the walls and roof, preventing drafts and leaks, and controlling humidity levels inside the building.
Air and vapor barrier membranes come in a variety of materials including, but not limited to, plastic films, membranes, or sprayed-on coatings, and are applied to the inside or outside of a building's structure.
Having a proper air and vapor barrier membrane installed in your building can help prevent a number of problems, such as mold, mildew, and rot, that can lead to costly repairs down the road. It can also help improve the overall energy efficiency of your building by preventing drafts and controlling humidity levels, which can save you money on heating and cooling costs.
Installing an air and vapor barrier membrane is a complex process that requires knowledge and experience in building construction, so it's important to choose a professional waterproofing contractor with a proven track record of successfully installing air and vapor barrier membranes.
In short, air and vapor barrier membrane are an important part of waterproofing and energy efficiency of a building, it can protect the building from water and vapor, prevent mold, mildew, rot, drafts and improve the energy efficiency, its a complex process that need professional help.