Sealing Grout after Cleaning Grout is a very porous material making it a  time consuming and difficult task, especially if it is a DIY project. Being that it is porous makes it not only a great place for soils to accumulate but also mold, mildew, bacteria and odors. Sealing your grout will protect it from these contaminants and help make the task of cleaning it easier not mention that it also helps from being stained by certain spills. Should all grout be sealed?  No. Only cement-based grout should be sealed. Synthetic grouts, such as Epoxy and Urethane don't need to be sealed neither does grout that has been recolored or color sealed. How often should I have my Grout Sealed?  Depends on the amount of traffic and the maintenance. Under high traffic conditions sealer should be reapplied yearly along with a professional cleaning. Under normal conditions, about every 3 years for the simple fact that these sealers break down over time. Absolutely Kleen has chosen to use a s