Concrete crumbling under wall footing?

[thewooddogg]

Hello,
I just found this forum while hunting for some answers. Recently, while preparing to sell my house I moved my desk from the corner of one of my rooms and found some problems. The baseboard along one of my walls was pulling away. I figured big deal, I'd just reattach it. Upon further inspection I noticed that the concrete under the wall seemed to have crumbling and gave way about 1/4th an inch.

So I've called the warranty department for my home (home is about 3 years old) and they're going to come take a look at it. However, I wanted to gather as much information about the issue before speaking with them.

I'm going to include a link to pictures of it below.
Two things to note:
1.) The carpet on one wall has 2 of those spike strips.. as it they did double just in case a problem. I don't think that's normal.
2.) They caulked the corner and some of the left walls baseboard. Thats not supposed to be normal either.

My questions are, do you guys think this is a serious issue? How much would it cost to repair? Would you consider it a "load-bearing" problem (that's all my warranty currently covers). Any other information or advice would help also.

Here's the link:

http://members.cox.net/woodysxj/house/house.htm

[doyle]

Wow! Looks pretty serious to me for a 3-year-old home. Hopefully your structural warranty will cover the repairs.

[thewooddogg]

I forgot to mention... because of the two items I said to note above (the carpet spike strips and caulking) that this was a problem even before I actually moved into the house and they tried to cover it up.

[mjpliv]

Can you give us a little more information.

What type of structure are we talking about. Is this slab poured inside a concrete foundation wall? I see you placed a screw driver in one of the pictures. Was this to indicate the presence of a gap? Was the carpet "original" from the day the house was completed, or was it added after the house was lived in for a while? What material are the moldings made of (wood, MDF, etc.)? Any idea how thick the concrete is at that point? Are we looking at a finish applied directly to the concrete wall surface?

With regard to the caulking on the moldings I am betting that you are looking at a product called "DAP" or something similar. It is a very flexible, paintable filler used by finish carpenters to fill any voids left between the moldings and an irregular wall surface. It's is also used in areas where the joints might have been a bit sloppy. It should feel somewhat rubbery.

Have you lived in the house since it was built?

[mreynolds]

To go with the previous post, what type of climate are you in? How about the soils below? What are they like?

[thewooddogg]

Thanks for the replies... I'm going to answer each questions as well as I can.

What type of structure are we talking about.
- It is a two-story home around 1550 square feet.

Is this slab poured inside a concrete foundation wall?
- I don't think so.. but I'm not positive either. I apologize that I'm not to familiar with the types of pourings.

I see you placed a screw driver in one of the pictures. Was this to indicate the presence of a gap?
- Yes.. the gap between the wall and the baseboard was noticeable and was not always there. I put the screw driver in there to bend out the baseboard and look why it wasn't holding to the wall. Two things I noticed was 1.) the nails are still stuck in the wall but have been bent up and pulled out of the baseboard (almost like the wall dropped down) and 2.) the crumbling concrete.

Was the carpet "original" from the day the house was completed, or was it added after the house was lived in for a while? What material are the moldings made of (wood, MDF, etc.)?
- Carpet is 100% original. It's been there since I picked it out at the design center and they installed it. I think the baseboards are made of regular wood. Maybe pine or something?

Any idea how thick the concrete is at that point?
- I don't, but I could ask the warranty guys.

Are we looking at a finish applied directly to the concrete wall surface?
- Once again, I apologize, I'm not 100% I understand what that question means.

Have you lived in the house since it was built?
- Yes

what type of climate are you in?
- I live in Phoenix AZ. So it's pretty hot..

How about the soils below? What are they like?
- The most I know about the soils is from digging in my backyard for sprinklers and stuff. It seems like a lot of clay. Not very sandy.

The warranty guy showed up yesterday... the one thing he did specifically tell me was that he thought it was odd that there was two carpet spike strip things and he thought it was odd that caulking was used. He said neither was a normal thing for them to do.

Thanks for any help you guys can give me.

[mreynolds]

I will defer this question to rich, he knows more than me. Could this be an issue with an expansion joint, where the concrete is contracting as it cured? :?

[Rich]

It looks to me like they ran out of concrete while pouring and you've got a cold seam. A cold seam is essentially where they've placed concrete and it begins to cure before they can pour the adjacent concrete. There is not as good of adhesion between old and new concrete - creating a weak joint.
What mreynolds just mentioned about expansion could very well have played into this if they only patched the area instead of chipping down and replacing it correctly.
Accidents do happen.. the difference between a decent contractor and a great one is the great one will fix it correctly.

[thewooddogg]

Thanks for the replies again..

I'm trying to understand the answer...

The area I'm showing you is actually the corner of the house.. so there's no adjacent concrete slabs on the outside of those two intersecting walls.

Is this problem a load bearing issue? would it be expensive to fix?

[Rich]

Not adjacent walls.. adjacent concrete. Fill a glass half full of jello mix and refrigerate.. when it begins to setup fill the rest of it with jello mix. Where the two "pours" meet is a cold seam.
It could be a load bearing issue - especially looking at the last 2 images. There are some options to mend it with hydraulic concrete but there is no guarantee that it will actually fix the problem. Being that the crack is vertical it could also be a soils issue where it wasn't compacted enough and the foundation is actually bending enough to crack it.

[mjpliv]

It is difficult to offer sound advice to you regarding the concrete slab just looking at the pictures. It would help if we knew the construction details.

If I see what I think I see then I believe you can relax a bit. When I asked you if the wall finish was applied directly to the concrete foundation wall I was trying to get an indication of how far the slab was from the wall. Perhaps the walls I see are wood framed walls above grade but sitting on top of the foundation walls at that point.

In most cases the gap between a non-structural slab and the foundation walls should be between 5/8" and 3/8" from the foundation wall. In my personal experience this gap is usually created by placing and fiberous expansion joint material against the foundation wall prior to pouring the floor. It is also my experience that this material is left in place but this may not be the case in your area.

When I asked for the time frame between the completion of the house and date of the carpet insulation I was trying to determine the state of the concrete at the time they installed the carpet tack strips. If they were installed within 2-3 weeks of the floor being poured then the concrete would still be "green" and would easily accept the carpet strip nails. I think what happened here is the concrete had passed the "green" stage when the strips were installed. When the carpet layer installed the "outside" strip that close to the edge of the slab I imagine that the nail on the far left of the picture simply created a stress fracture and the edge just popped of. Simple as that!! If you look at the largest piece of loose concrete, the broken edge seems to run towrds that nail. After he/she did this they appear to have added an additional carpet strip to -

1. - compensate for the nail that broke the concrete

or

2. - as a backup for the outer strip in case more of
the concrete edge broke away.

If your slab assembly is built the way I think it is then it is a non-structural component. The slab itself does not hold anything up except you, your carpet and furniture. The fact that and edge has broken off does not indicate any cause for alarm.

My only real concern in all of these pictures is the lack of some sort of seal in the expansion joint. I would have expected to see at least some sort of mastic sealant placed there.

[mjpliv]

Rich, take another look at those last two pictures. At firts glace it looks like an open crack and I thought the same thing you did. I Looked at it again and noticed the the top of the "open" crack is tight. Is actually just some spalling of the surface. I am not sure if this house is in an a area subject to frost but it looks like there was a crack in the non-shrink grout under the door sill and some water got in and froze, popping out a few pieces of the surface.

[Rich]

Hmm... I was looking at this as if it were a slab on grade and poured down monolitic to the foundation wall.. but now that I look a little closer I see what mjpliv was talking about and the expansion joint next to the wall.
I'm still not sure about the crack in the last 2 of 3 images. I almost want to agree with mjpliv - and I probably would 100% if I could see through the door jamb :)
I agree it is very difficult to diagnose these types of problems.. not that your images are not good or anything - just that there are so many unknowns. Any more information you can give wooddogg?

[thewooddogg]

I'm not sure if any of the information I can give would be that helpful to experts. I could ask specific questions of the warranty guys if I need to. I believe how they build houses here in AZ is to pour the slab on concrete, then build the walls out of 2*4's and stand them up and use those wedge type nails to hammer the bottom 2*4 to the concrete. I can take pictures of the outside of the house and foundation if you need me to. The crack on the outside foundation is about 12 feet away.

I thank you guys for all your help... I'm just trying to understand what might of happened to it and how serious it is. If it's not load bearing the warranty won't fix it and I still want to be able to sell it.

[kdavis]

Something else that might have happened is that the concrete considering it is in AZ might have not stayed hydrated. Creating a weaker concrete because water was no longer present in the matrix, but I can't tell really from the pictures if it was honey combed or not. Even more you metioned that the soil was a clay. With clays it takes a long time for them to actually compact due to the loads of the house and three years is not unheard of for that type of soil. Structures built on clays don't always settle at the same rate and clays also will expand and contract depending on the moisture conditions of the soils not to mention the effects of the water table might have in the region.

[thewooddogg]

Hello again everyone.. just a follow up..

I have good news.. however I still have doubts.

The warranty people have called me and told me there is nothing wrong and that's just normal settling of the house and it's not a load-bearing problem. They said they are also going to give us signed paperwork saying so. So I guess I'm in the clear for selling the house now. I just still have doubts about the answer...

[Rich]

Yeah I would agree with your doubts. Settling occurs randomly in most cases.. not when you walk on it :)

[thewooddogg]

Now you're scaring me Rich! Lol..

What did you mean by that last statement?

That you agree with my doubts in it not being the correct answer?

The "walk on it" part confuses me.. the wall crumbling is under the wall not under where we walk..

[mjpliv]

Have you consulted an engineer? Might be worth your while to spend a couple of hundred bucks for an independent, unbiased opinion. The warranty people signing a document saying the problem doesn't exist sounds like a brush off.

[Rich]

Geesh.. I apologize wooddogg. I just went to the last post and thought this was from another post regarding the squeaky floor.. :(

Now you're scaring me Rich! Lol..

What did you mean by that last statement?

That you agree with my doubts in it not being the correct answer?

The "walk on it" part confuses me.. the wall crumbling is under the wall not under where we walk..

[thewooddogg]

LOL Rich! It happens! you got me scared there!

Here's a copy of what they wrote on the signed work order.

"After checking, there is no cracking on stemwall, stucco wall, or interior wall(drywall). It has been determined that there is no damage to any load bearing footing."

You think this will cover me in selling the house or should I get an unbiases opinion also? The warranty has a built in arbitration part that says I can submit it for review to another company that the warranty has contracted.