How do I asses if my grouts have been sealed or not?

It doesn’t require professional skills to be sure whether the tiles have been covered with sealant or not. All you need to do is spritz a few drops of water and let it say for about 5 minutes before wiping it off with a cloth. If the water soaks in or leaves a mark on the floor surface, it is a clear indication that there is either n sealer or a reapplication is necessary.