Silane, siloxane, and siliconate based water repellents have been used for decades to protect buildings against moisture and consequent physical, chemical and biological deterioration. These silicone based water repellents in comparison to film forming coatings do not seal the surface of concrete and masonry. They instead modify the pores of the substrate such that the absorption of liquid water is suppressed; the pores, however, remain open and water vapor diffusion is not affected.
For a long time it was thought that it would not be possible to create storage stable water based water repellents. One of the main demands for these repellents is that they must penetrate well into the substrate. A water based water repellent sealer is surface applied, invisible and very effectively increases the durability of concrete. Due to the small size of the mono-molecular layer, there is little or no change in its aesthetic appearance. Water repellent sealers change the surface tension of mineral substrates and produce a water repellent surface to keep water and aggressive water-soluble salts, such as chlorides and sulfates, out.
In structures on and below grade water should generally be kept out and away to prevent damage. The most pervasive form of concrete damage is surface scaling from freeze-thaw. Other forms of damage include alkali-silica reaction (ASR), chemical intrusion and corrosion of steel reinforcements. Siloxa-Tek 8500 can block up to 99% of surface moisture. The active ingredients seal the pores within the substrate adequately blocking surface moisture while still maintaining the concretes ability to breathe. It will not significantly modify substrate appearance or traction and will only wear away if the concrete surface itself wears away.