Excessive rain can cause damp patches on walls. The moisture attracts dirt from the air, so that the walls become dirty. Mould can then form and green algae can grow. If the damp is transferred indoors, mildew patches can form on the interior walls, creating a damp and musty smell. By treating the wall with HG water seal for outside walls, water can no longer penetrate the wall, so problems caused by excessive moisture are unlikely to occur. HG water seal for outside walls has been developed using the latest chemical technology. It allows the wall to continue to breath, is very simple to apply yet remains active for at least 10 years. Clean the surface to be treated beforehand using HG tile power cleaner (polish, wax and dirt remover) (HG product 19). Nitrous deposits or masonry deposits should preferably be removed using HG masonry efflorescence remover. Remove green deposits preferably using HG green slime remover. Apply HG water seal for outside walls using a brush, roller or pump spray. Do not treat more than 2 m2 at once and always work from top to bottom. Apply the product in horizontal stripes from left to right. Always apply 2 or more layers to a surface, in order that it becomes saturated (2 thin layers are preferable to 1 thick layer). Always apply the various coats of HG water seal for outside walls wet on wet. In other words, the previous coat must not be fully dry before applying the next coat. Do not apply in the sun or on warm walls. Depending on the porosity of the surface to be treated, 1 litre of product is sufficient for 2 to 10 m2 surface area.