Contractor Talk - Professional Construction and Remodeling Forum banner

1 - 20 of 55 Posts

·
Registered
Joined
·
13 Posts
Discussion Starter · #1 ·
uploadfromtaptalk1407025042735.jpg uploadfromtaptalk1407025054913.jpg uploadfromtaptalk1407025072529.jpg

Good afternoon everyone. I'll start by saying that I'm an HVAC tradesman, not concrete. However, I figured I could get punted in the correct direction here, and get advice on if I need to have this addressed right away.

I just bought a house about two months ago, and recently noticed the concrete on the edge of my slab starting to flake, along with my block wall. I could be wrong, but am nearly 100% sure this wasn't like this, or at least as noticeable 2 months ago. I live in Henderson Nevada, where it's dry as a bone. Hardly any rain. I had a pest control spray applied around the perimeter of my house and wall a month ago or so, and that's about all that's been done. I don't remember it being like this before that. Even those red rocks around the area were softened and turning to dust. Any idea what may be happening and what I need to have done to stop this?

Thank you
 

·
Registered
Joined
·
686 Posts
Interesting. Normally, with the first two photos, I'd say that it's likely just a subpar mix used on the slab, but that third photo has me baffled. Is that the splitface block disintegrating at the cinder line?!? And did you pull some away in the foreground?

I have never heard of pest control using anything that could cause damage to concrete or cinder, but you may be on to something. Bizarre. I'm gonna dig a little......
 

·
Registered
Joined
·
1,255 Posts
If check the PH. If the PH is below 9 then it's being attacked by something and deteriorating the cement paste exposing the aggregate. That's what I would do first. Concrete needs a PH of 10-13 to remain stable.
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #4 ·
Thanks for the replies and suggestions. Yes, that block wall is disintegrating right at ground level, where the rocks were touching it. I noticed a gray powder accumulating at the bottom of the wall, and that's what prompted me to pull the rocks back away from the wall. That's when I saw the disintegration. I then noticed the same powdery buildup at the base of my slab, and again pulled those same rocks back a bit to find multiple areas that appear to be disintegrating. All areas that were disintegrating had those small red fill rocks making contact. As I said, they were also disintegrating. As I was using a shovel to pull them back, they were turning to a red powder, just pulverized.

I'll do a little research on how to check the pH level. Thanks
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #5 ·
Also, the house and wall are 17 years old, and this is the only area of the house that this is happening. No other sides or areas have anything that looks like this, and also this is the only area that has those rocks. I'm just wondering if it has something to do with those
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #6 ·
Also, the house and wall are 17 years old, and this is the only area of the house that this is happening. No other sides or areas have anything that looks like this, and also this is the only area that has those rocks. I'm just wondering if it has something to do with those
uploadfromtaptalk1407087183908.jpg uploadfromtaptalk1407087202603.jpg

Just to show, here is what I mean when I say the rocks are also disintegrating. I picked one up, and ran my fingers across it, and it began to pulverize and fall apart in my hand .
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #9 ·
If check the PH. If the PH is below 9 then it's being attacked by something and deteriorating the cement paste exposing the aggregate. That's what I would do first. Concrete needs a PH of 10-13 to remain stable.
Are you talking about checking ph of the concrete itself? Or of the soil and rock in contact with it?

Thanks!
 

·
CCC
Joined
·
275 Posts
I wonder if someone didn't try and clean that wall at one time with a heavy acid like muriatic acid or something then wash it off and it puddled at the bottom edge and eventually ate into it? Bug spray wouldn't have done that.
Having said that, your wall isn't going to magically going to fall down. Like you said, Henderson gets very little rain or freeze thaw cycles to keep pounding on it. I wouldnt worry one bit about it to be honest.
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #12 ·
I wonder if someone didn't try and clean that wall at one time with a heavy acid like muriatic acid or something then wash it off and it puddled at the bottom edge and eventually ate into it? Bug spray wouldn't have done that.
Having said that, your wall isn't going to magically going to fall down. Like you said, Henderson gets very little rain or freeze thaw cycles to keep pounding on it. I wouldnt worry one bit about it to be honest.
Thanks for the response! Do you feel the same about where the edge of my slab appears to be doing something similar? I'm just wondering if it's something to be concerned over, and get a concrete contractor over to check it out, or if I'm being paranoid. I'm more concerned with the slab, shown in the first couple pictures, as opposed to the block wall.

Thanks
 

·
Registered
Joined
·
271 Posts
I don't know of any pest control pesticide that eats concrete. Maybe some herbicides like roundup. Muriatic acid wouldn't surprise me. People spray all kinds of stupid stuff to kill bugs or weeds. Muriatic acid, bleach, formaldehyde, all of which I have heard of people using lately.
 

·
Registered
Joined
·
11,384 Posts
I'm not a concrete guy, but that looks like salt damage. Out east, some of the concrete sound barriers that run along the interstates are doing the same thing from the bottom up (from snowy winters, dispersed salt, then plowed). Looks like your soil composition doesn't particularly like that wall. Even if it's alkaline, it might have excess salts. Maybe replacing the soil adjacent the wall would slow it down. Just a guess. You guys were once an ancient sea and now have lots of sandstone, so it's plausible.
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #16 ·
I just need to find a PH testing kit and I'll be checking my soil in that area. I'm originally from Massachusetts, so I've definitely seen what salt does to concrete and brick
 

·
CCC
Joined
·
275 Posts
Thanks for the response! Do you feel the same about where the edge of my slab appears to be doing something similar? I'm just wondering if it's something to be concerned over, and get a concrete contractor over to check it out, or if I'm being paranoid. I'm more concerned with the slab, shown in the first couple pictures, as opposed to the block wall.

Thanks

Is your house going to crumble and fall down? Not a chance. This just looks superficial and pretty ugly. Unless you can start to pull rocks out of it and break it up with your fingers would I even begin to worry. If that was the case, id go rent a power washer from Home Depot and blast it real good then buy some concrete patch and fix it up. Or, go to a home development and look for a concrete finisher and tell him you have a side job for him and let him patch it. No biggie IMO.
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #18 ·
Is your house going to crumble and fall down? Not a chance. This just looks superficial and pretty ugly. Unless you can start to pull rocks out of it and break it up with your fingers would I even begin to worry. If that was the case, id go rent a power washer from Home Depot and blast it real good then buy some concrete patch and fix it up. Or, go to a home development and look for a concrete finisher and tell him you have a side job for him and let him patch it. No biggie IMO.
10/4. Thanks for the advice. I'll have someone seal/patch it and look at it. If I slide my fingers across it, lots of dust does come out and small pieces. It's pretty soft in that one spot.
 

·
Registered
Joined
·
2,940 Posts
If check the PH. If the PH is below 9 then it's being attacked by something and deteriorating the cement paste exposing the aggregate. That's what I would do first. Concrete needs a PH of 10-13 to remain stable.
That's the ph of lye, oven and drain cleaner.

I thinks you don't know what you're talking about. Cured concrete has a ph of about 8 to 8.5. Please don't spray your nonsense on this board.
 
1 - 20 of 55 Posts
Top