Over a long enough time can ants cause structural damage to a house, or other structure, built with concrete blocks?

We bought our current home new but the house was sitting complete and empty for about 2 years before we moved in. We have a small amount of ants each summer. I have had a little bit of success with any poison but obviously not complete success as they return each year.

We have some cracks in our house that are borderline structural cracks and we are having these assessed by engineers. They could be caused by a completely different reason.

However, is it at all possible that I am overlooking the potential damage that ants could cause to a block house?

2 Answers 2


Here in Florida we have a multitude of bugs. termites are terrible, however even more homes have issues with ants. However the issues are with the wood member of the homes and not the blocks. It is very unlikely that ants have caused cracks in your block. They definitely can use those cracks to get inside where you see them, ( and in the walls where you can't)
So to answer, No, the ants are not at all likely to be the cause of structural damage to concrete block. If you have hairline cracks that follow the block mortar lines it is most likely normal settling and seasonal expansion and contraction. if you have windows and/ or doors that are racked and difficult to operate then you have serious issues.


It depends on where you are and what else (in addition to the concrete blocks) your house is made of.

Ants don't eat concrete, bricks or mortar. Where I live, they are also considered safe for wood (but I am not sure they are safe for wood everywhere).

Ants are also not a health risk so in some cases they are an overall improvement compared to e.g. cockroaches (an ant track somewhere in the building means no cockroaches in the whole building). Ants could also be the last line of defense against bedbugs or, to some extent, wood-eating insects (if modern approaches are not available or not applicable).


The fact that you have ants inside means they have an easy entry. They don't nest inside.

Their usual entry points are either wide cracks in some mineral material (concrete, mortar) or gaps between such material and wood (window/door frames).


No, you don't have "little bit of success" with them. When we lived in a house with an ant problem, ants appeared each summer and then disappeared after 1-2 weeks by themselves. This is likely related to their lifecycle or the season. You can't really poison them (short of finding the nest, digging it and poisoning them there). You put poison, few of them die, the other ones just take note of the fact and avoid the problem place.

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