I just found that there is a crack in one of my glass blocks. I noticed that it seems to have water inside. What is the likely cause of this, and how can I repair it? Should I be worried about structural damage?
It's glass...it's a fairly rigid material and will not flex like other potential building materials such as wood, mortar, etc. So, if the house settled, the block may simply have been under enough stress to crack it.
Or, maybe someone shot it with a BB gun.