External wall waterproofing is the process of protecting the exterior walls of a building from water penetration and moisture damage. It involves applying various waterproofing materials and techniques to create a barrier against water intrusion.

Here are some commonly used methods for external wall waterproofing:

1. Exterior Waterproof Coatings: Waterproof coatings are applied directly to the exterior wall surface. These coatings form a protective layer that prevents water from seeping into the wall. The coatings can be in the form of liquid membranes, elastomeric coatings, or cementitious coatings.

2. Waterproof Membranes: Waterproof membranes are thin layers of material that are applied over the exterior wall surface. They provide a continuous barrier against water penetration. Membranes can be made of bitumen, modified bitumen, PVC, EPDM, or other synthetic materials. They are usually applied in multiple layers for enhanced protection.

3. Cementitious Waterproofing: Cementitious waterproofing involves applying a cement-based coating or slurry to the exterior wall. The cementitious mixture fills the pores and capillaries in the wall, creating a waterproof barrier. This method is commonly used for concrete walls.

4. Liquid Applied Membranes: Liquid applied membranes are fluid coatings that are sprayed or rolled onto the exterior wall. They cure to form a flexible, seamless membrane that prevents water infiltration. These membranes are often made of polymer-modified asphalt, polyurethane, or acrylic.

5. Insulated Waterproofing Systems: These systems combine insulation and waterproofing into a single application. Insulation boards are fixed to the exterior wall, followed by the installation of a waterproofing layer on top. This method provides both thermal insulation and waterproofing properties.

6. Drainage Systems: In some cases, external wall waterproofing may involve the installation of drainage systems. These systems are designed to collect and redirect water away from the walls. They may include the use of weep holes, drainage mats, or channels to ensure proper water management.

It’s important to note that external wall waterproofing should be performed by trained professionals who have expertise in waterproofing techniques. The specific method used will depend on factors such as the building materials, climate conditions, and severity of water penetration issues. Consulting with a qualified waterproofing contractor or engineer is advisable to determine the most suitable waterproofing solution for your specific needs.