This question actually reminded me of an issue with my exterior walls. I have the same problem with the vertical mortar being eroded/missing from several bricks at ground level on the exterior of my house. I live in Alabama, so we don't have much severe weather (unless you count ridiculous humidity), and I have no idea how this could have happened. The rest of the mortar is fine, but only a few joints are completely missing. Is there a way to prevent this from happening? Is this some purposefully built structural feature that I'm just oblivious toward – they seem to be fairly regularly spaced.
When the home inspector came by before we bought the house, he didn't mention anything about them, and I didn't really notice them until we moved in.
Best Answer
The gaps are there intentionally. They are weep holes which allow moisture to escape from inside your walls. This website has some more information as well.