You might be surprised to find out that grout cannot be sealed at the time of tile installation. Newly installed grout usually needs 72 hours to cure before a sealant can be applied to it. Since sealer is not necessarily a “requirement” of a tile and grout job, contractors will often skip this important step for one, or both, of the follow reasons:
Reason #1: It would require a return trip to the job sight, 3 days or longer from the installation date. This is often difficult for busy contractors.
Reason #2: They would incur additional man hours as well as the material costs associated with the cleaning and sealing the newly installed tile and grout.