Grout fills the gaps that hold tiles together, so it is read as the small daily efforts that keep things in place. Crumbling grout points to neglected details starting to show.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.