# Is something eating the mortar?



## shark_bait (Apr 28, 2014)

Every other month or so, I notice a small pile of mortar dust on one side of the mantel. I vacuumed it before I thought about taking pics unfortunately. I assumed it was because most of the mortar around the fireplace is old and powdery to the touch (I'm planning on redoing it in the near future). However since it's only on this side that the pile appears to be consistently larger than other areas, I wondered if it was due to insects. I took a knife and scrapped down between the wood frame and brick and noticed these shell-like things. They are hollow and brittle like an old egg shell or whatnot. Does anybody know what these are? I've never seen any insects inside and it looks normal from the outside as far as I can see unless it's a draft from that angle of the house?


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## jmon (Nov 5, 2012)

Idk. I believe there is an insect that nests in mortar. Crazy I know.

Take the picture or specimen if you still have it, to your local county extension agricultrual department for identification and how to get rid of them. Just a suggestion.


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## PAbugman (Jun 29, 2010)

Picture #3 are cockroach egg cases. Probably old as you are not mentioning a roach problem. Search “ootheca”; yes that is spelled right. Not sure that any insect is eating/chewing the mortar. 

There is a “mason” bee that chews into old, bad mortar but that is rare and always on exterior.


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## shark_bait (Apr 28, 2014)

Ah, yes you are right about the cockroach egg cases, I was searching the net for rare insects that could eat mortar and leave these shells behind and didn't even think to check the obvious like cockroaches. That makes sense since these were only found inside and in a tight crevasse but they aren't causing the dust in this case. I haven't seen a cockroach in over a year or so, so these must be old.

I do currently have carpenter bees that are boring holes in my deck just behind the fire place here but I've killed 3 this week and haven't seen any since. I doubt they would be doing this to the mortar though?


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## jmon (Nov 5, 2012)

Maybe the mortar is just old and deteriorating a bit. No biggy. If concerned, you can have a local certified mason look at it, to rule out anything serious.

I believe they make a multi purpose sealant that can be put right on the brick and mortar to help prevent the mortar dust from falling around your mantel. It's clear and won't affect the color of the brick. Not sure what it's called, but your local big box stores should carry it. You can diy, and give it a try, see if it helps. Just a suggestion. 

As mentioned already by the pa bugman pro, I agree, serioulsy doubt it's an insect boring into the mortar. You would see mortar dust all the time, not every other month or so.


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