Water Insulation on Facades

Water is an essential material for all living organisms. It can be found either aboveground or underground all around the globe and structures are continuously interacting with the water as well. Water is a polar molecule having tendency to stick to one another. This attraction is called cohesion and it enables water to create intermolecular interactions with other materials resulting in “wetting” them. Being a universal solvent, water is more destructive if it is in direct contact with building materials and moving compared to being still. It has also an ability called capillary action enabling it to climb upwards through thin tubes.


In general, water affecting the structures can be classified as groundwater or surface water. Water can enter the structures by gravity, hydrostatic pressure, weather streams and surface tension. Gravity allows water to infiltrate into buildings, hydrostatic pressure allows groundwater to apply pressure to the building where groundwater level is higher than the bottom of foundation, weather streams allows water to move mechanically and surface tension allow water to penetrate through the joints, connection points, cracks etc.


Humidity is the concentration of water vapor present in the air. Absolute humidity is the water content of air in grams per cubic meter. Relative humidity indicates a present state of absolute humidity relative to a maximum humidity given the same temperature, expressed as a percentage. When relative humidity reaches 100%, it means air is totally saturated with water and if the temperature falls at that point, condensation occurs. Condensation occurs as sweating on the surfaces of building materials or inside of them.


There are several precautions taken for water insulation on facades. The usage of water repellant can be counted among these measures. Water repellants are manufactured with silane/siloxane and they create a thin, transparent, hydrophobic (ability to be repelled from water) layer on facades blocking water to stick to the surface.


Polyurethane (PU) based sealants which are used together with Betonex CBOARD Panel and Decorative product groups are among materials used in water insulation on facades. Generally, sealants act as joint filler and provide impermeability. Their flexible form allows facade panels’ natural movement. Apart from organic polyurethane-based sealants, there are inorganic silicone-based sealants manufactured as well. Mechanically, they are not as strong as PU-based sealants, yet their inorganic structure protects them from the harms of environmental conditions. During the manufacturing, some additives are added into the PU-based sealants increasing their durability against environmental conditions.


Where open joints are preferred on a facade, moisture barrier aids the water insulation. Moisture barriers are technical textiles manufactured from high-density polyethylene (HDPE) or polypropylene. These textiles are waterproof yet lets air pass through and they are installed on top of heat insulation layer of the facade. They help moving away the water come by condensation effects.


To prevent water penetration by rain, snow, wind etc. mechanical effects, the decorative elements like Betonex CBOARD Cornice and Jamb are manufactured with a slope on top of them preventing water puddles and directing water away. In addition, usage of weather drips prevents rainwater moving on the surface of the building element and pours it away.