Silane / Siloxane sealers are hybrid products that coat and penetrate surfaces of concrete, mortar,  and other masonry to chemically react in such a way that hydrophobic surface is created. This protects the surface from water and increases resistance to cracking, spalling, pitting, freeze-thaw damage, mold and mildew growth, and efflorescence formation.

Silane and Siloxane are both derived from the Silicon family. They are very closely related but have significant performance differences. Silane molecules are smaller, allowing them to penetrate into tight spaces and pores whilst Siloxane molecules are larger, performing better on surfaces. 

Both can be used as water based and solvent based, bring unique properties to each. Water based mixtures are better on porous surfaces, whilst solvent based mixtures are better on dense surfaces. This is due to the larger polymer size in water based mixtures. 

They can be applied via spraying and rolling/brushing on.