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bxju 03-16-2013 12:53 PM

Something seems to be eating concrete
UPDATE-UNBELIEVABLE RAT DAMAGE TO CONCRETE...I AM ADDING A PICTURE TO PAGE 2 TO SEE THE VERY QUICK PROGRESSION OF DAMAGE CLEARLY CAUSED BY RATS. I had no idea that rats could so quickly eat through concrete block and do such damage, if you scroll through the pictures, the first being taken last Friday and the last being taken just now, you will see now three large holes completely through the block and now stuffed with steel wool. The two upper holes were much smaller last evening and the bottom hole was not even in the block yesterday, I would like to see night video of what must be a rat haven at night. This is in a fairly good area of St Petersburg, FL right off US 19 but right next to a salt water Marina.

ANOTHER ADDED PHOTO NOW BELOW IN NEW POST, THANKS! I have a photo of what appears to be something eating the concrete block behind by office. Pest Control does not know what it is. I cannot figure out how to post the photo. Is there a simple point and click or can someone send me a private message with an e maill address and I will forward and you can post. No one can figure out what is causing this, builidng is about 30 years old and in good shape and there are recent large (4" to 6") holes in the concrete like a woodpecker would cause and a large pile of debris down below like termites or ants would cause.


joecaption 03-16-2013 03:02 PM

Rats are the only anaimal I've seen eat through concrete.

GBrackins 03-16-2013 04:37 PM


Originally Posted by bxju (Post 1138582)
I cannot figure out how to post the photo.

make sure the photo is less than 100kb

bxju 03-16-2013 07:32 PM

1 Attachment(s)
Attachment 67470

this was taken yesterday....the top hole is A/C PVC drain vent, but this space has been unoccupied for 6 months and A/C not running. This is fresh, not there a few days ago. the pest company said not rats,, the bait trap has been there for a while and we do have rats in area because of a bagel shop and at sports bar are also in the center. City is St Petersburg, FL

rckkrgrd 03-16-2013 10:44 PM

I believe there is acidic water coming from the drain and eroding your concrete. It dissolves the cement leaving the sand. Put an extension on your drain.
I think the paint held it together till recently.

creeper 03-16-2013 11:50 PM

And when you are finished with the repair do not wash your hands in that water...:eek:

mj12 03-17-2013 07:35 AM

Is that the only place? If it is in other places then it is not your water.

carpdad 03-17-2013 08:08 AM

A joke maybe? Volume removed and volume of sand don't seem to match.:laughing:

Fix'n it 03-17-2013 08:58 AM


Originally Posted by carpdad (Post 1139238)
A joke maybe? Volume removed and volume of sand don't seem to match.:laughing:

yeah, no doubt.

bxju 03-17-2013 11:27 AM

I doubt it is a joke, surely not by me and I would not know why or who. The Optician that parks nearby had already called the landlord by the time I called him. The landlord came out, the pest control people came out and no one knows what is causing it. It clearly looks like a pile you would see from carpenter ants eating wood and the holes look more like a woodpecker pecking holes in wood. I think the fact it is directly under the drain is a factor, but again the A/C has not run in this unit for at least 6 months and nowhere else in this large center is it doing this. In addition, this all occurred over a week or so as it rained very heavily the previous week and would have washed this uniform pile away.

rckkrgrd 03-17-2013 11:49 AM

Animals leave tracks and would not have done such a neat job. I doubt that a jokester could have been this neat either. The paint that was holding it all together may have failed because of the rain. I stand by my original diagnosis of acidic water. It does not have to be noticably acidic to affect concrete over time. Think of acid rain which doesn't bother you but has bad effects on concrete. Drop an uncoated nail in a bottle of coke and leave it for a couple days to see what I mean about acid effects of liquids that you do not even think of as acidic.

bxju 03-17-2013 01:49 PM

If the building were wood, the area under the drain would be first to attract termites. I agree that acidic water erosion seems the most logical but it is very strange to see it suddenly occur in this volumn over a very short time period. In addition, I would think as large as this center is, some other areas would show some wear. This is on the West coast of FL (about 3 miles from the Gulf) and it rains often and this building was built in mid-80's and shows no sign of deterioration anywhere else. Anyone else ever seen concrete block deteriorate so quickly (a week or so)? And is A/C evaporation going to be so acidic that we should all ensure that it does not come in contact with any concrete or just concrete block as my home a/c runs off onto an added concrete deck.

rckkrgrd 03-17-2013 01:58 PM

I think in this case the paint kept it all in and out of sight until the paint failed for whatever reason and making it appear as if the erosion was recent. Air pollution causes any condensation to be acidic, particularily if it contains suphur such from vehicle exhaust or coal burning power pants. I am betting that this instance is in a high traffic urban area.

gregzoll 03-17-2013 02:06 PM

Most likely they packed the blocks with sand, to not only soundproof them, but to also help with fire control, to allow the walls to stand longer. I am going to agree, that it is something else eating the block foundation. These are the most common that chew through concrete: rats, mice, raccoon, opossum, shrews, voles, moles, chipmunks, ground hogs, muskrat, otter and skunk.

rckkrgrd 03-17-2013 02:38 PM

Good point--I can't tell from the picture but that could be loose fill insulation as well. Animals usually do not chew for no reason. Food or salt are the usual motives. I don,t think the drain water could be salty but who knows.

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