While we all know how strong concrete is, not everyone is aware of how vulnerable it is to moisture. Being a porous material, water and other liquids can seep into the surface and slowly destroy the concrete from within. However, you can combat this by hiring a San Francisco, California concrete company to paint or seal your concrete surface. While this is not a once-and-for-all solution, if you reseal or repaint periodically it can be. San Francisco concrete contractors recommend testing the sealing annually by dropping some water on the surface and observing if it gets absorbed or not. If it soaks in, it’s time to reapply.