I've got a house from the 1970s with lime mortar, and I've noticed several holes showing up in between the bricks. I'm curious about what might be causing these holes and how I can prevent them in the future. Here's a link to some images I took: https://imgur.com/a/HGh0NtQ.
3 Answers
It sounds like these holes might be due to poorly mixed mortar. Unfortunately, there's really not much you can do to prevent it once it's there. If you only see holes sporadically and not throughout, it might not be erosion. Ultimately, I'd say just keep an eye on it and repoint when necessary to maintain the integrity of your bricks.
I think birds might be involved. They sometimes peck at mortar for the calcium in the eggshells, which could create holes. It might be worth looking out for any nests!
In my experience with a house from the 30s, I had similar holes, and I’ve noticed they don’t seem to be weeping holes. Sometimes the structure's design can make a difference, too. Not really sure how to fix it, though—just sharing my experience! Still standing after all these years, so maybe it’s not a huge issue?
Interesting! I wonder if we might just have different causes—like some sort of pest causing the holes? Just a thought!
What do you think about the possibility of those holes being caused by insects like wasps or mortar bees? I’ve seen some pretty deep ones that look a bit random.