Hello! I have a colonial house with the master bedroom shower upstairs. The house is 9 years old. A week ago I noticed some water mark at the roof of the downstairs floor exactly below my upstairs shower. Then I noticed a hairline crack between the inner wall and floor of the shower. We did not use that shower for a week. The water mark did not deteriorate after that. What kind of sealant/grout I need to use to repair the crack?

:confused:

The wall and floor of the shower are both tiled. -- Shahgir

Silicone caulk is probably the best for this type of fix. It is flexible and won't crack. However, it's always a mess to get off when you want to.

This is just a patch. There are better (more expensive) ways to fix this.