Holes in mortar

There were about 100 of these. Anyone know what may be eating
through the mortar? Carpenter ants?
No known moisture problems!



I think it is wasps.

Solitary bees and wasps

Not all bees and wasps live in colonies. There are over 200 species of solitary bees and wasps in the UK. Solitary bees lay their eggs in cells hidden away in soft sand, soil or mortar, providing each egg with its own food supply. Perhaps the best known solitary bee is the “leaf-cutter” which is responsible for cutting neat little semi-circles from the leaves and flowers of roses. Solitary wasps lead very similar lives to solitary bees, except that many of them are parasitic, laying their eggs inside the bodies of other insects. The larva then grows inside the living host until it is ready to turn into a wasp. Some solitary wasps are important for controlling many pest species.

… Cookie

Thanks Cookie,
So do you know the best way to stop them from eating holes in the mortar?

No but I might try a wasp trap the smell calls them in and they can not get out.
… Cookie

If the mortar is that soft that little wasps can move it, don’t bother about catching the wasps. Shouldn’t the whole chimney be structurally inspected by a licensed mason or at least be re-pointed to provide a proper protective outer layer of hard mortar?

It’s not a chimney, it is the side and front of the house.
The house was built in 1978 and the mortar is otherwise,
in good condition.

did you notice any yellow areas around these holes

Oh! In my area, 95+% of the brick I inspect is exterior chimneys…worst location for them. A chimney flue has to be warm/hot to “draw” properly but some time in the early 20th century, house designers started placing them outside the heated building envelope…in the cold!! Try and work properly out there!!

The Wood Energy Technology Transfer (WETT) Association that certifies the wood heating industry (technicians, sweeps, salespersons/advisors, inspectors) nationally in Canada would like to see exterior chimneys banned!!

Yes, reddish yellow. Thought it was probably Georgia red clay!

I have seen exterminators bore holes & spray poison into air space for termites???

It might be a good idea to Google this and increase your Knowledge on these little wasps .
I see it all the time .
Thanks … Cookie

have never seen holes like that in any masonry…guess we don’t have that species down here.