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#12473 - 06/07/08 04:58 PM Hairline cracks in foundation
SouthTexGopher Offline
Junior Member

Registered: 06/07/08
Posts: 2
Hi-

I've been reading all the great answers on this site and I've found it very helpful.

But...I'm still quite nervous about some things with regard to my own house. My house is a 1600 square foot, single-story home on a slab foundation. Three sides of the house are brick - the back of the house is siding. The foundation is coated in a stucco-like concrete parch coat. The house is located in north-central San Antonio where the soils are a combination of clay and limestone. The limestone bedrock is about 10 inches below the ground surface.

There is no interior damage to the wall or ceiling sheetrock, all the doors and windows function fine. I've uploaded a PDF with the locations of the issues.

I have hairline cracking in three places that I'm concerned about. The cracks are all about 1/32" in width or less.

Corners

Two of the corners have diagonal cracking running at a 45 degree angle beginning near the corner of the foundation and continuing toward the inside dimension of the foundation. The cracks are well below 1/16" in width and the width the same along the entire length of the crack. Not sure if this is important to mention, but these corner areas are only in the areas of the foundation that are topped in brick (that is, the walls above the areas have brick facing).

Garage

Last night I found another crack in the foundation wall of my garage. The foundation rises from the garage floor to a height of about 24" where it achieves the same level as the floor of the house. There is a hairline crack running from about three from the floor all the way to the actual top of the foundation wall. This crack continues into the concrete under the carpet inside the house for about a 10" length.

I broke out my cold chisel and hammer last night and cleared away the parch coat and a bit of the concrete. The hairline crack in the garage foundation wall runs through the parch coat and into the foundation about 3/4" - and then it stops. I ended up clearing away a V-shaped area of the concrete 3/4" deep at the deepest spot and about 3/4" wide at the outer limits of the "V" (the inner limit was 0" wide). After doing this and satisfying myself that the crack didn't extend deep into the foundation, I sealed up the area I'd chiseled with Quikcrete concrete repair (Vinyl Concrete Patcher). I applied this by packing the area with the product and then smoothing it with a trowel.

At the top of the crack - in the house itself - I chiseled out a bit - and the crack's depth is only about 1/16" at its worst. I left that alone.

The cracks in the corners have been temporarily sealed with the Quikcrete product as well - I've had quotes for repair of that using lathe and a new concrete parch coat.

Finally, there are a few shallow and narrow cracks in the floor surface of the slab (1/16" or less wide, 1/8" or less deep). One of these runs the width of my bathroom (about eight feet) and is not continuous - although it's generally in a straight line.

My questions...

1. Should I be freaking out? I'm losing sleep over this and stressing out constantly.

2. Did I do anything stupid in the garage by chiseling out the crack and patching it?

3. Does the repair that the contractor has told me about make sense?

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#12478 - 06/08/08 09:08 PM Re: Hairline cracks in foundation [Re: SouthTexGopher]
CR2 Offline
Member

Registered: 01/09/07
Posts: 502
Loc: New York
1- Keep it cool, don't freak out,it's perfectly normal and common, all concrete cracks, besides 1/32" is nothing.
2- Leave the small crack on the garage like that, it looks better than the patch work you are planning to do.
3- Repairs will make sense only if you have water filtration through the cracks, and not otherwise.
4- Hairline cracks are common in concrete walls and are not a major thing if proper waterproofing system is present, I think you have a solid foundation and you are worrying too much about it, relax and let it be (at least for now).
Feel better now? I hope so.
Good Luck!

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#12479 - 06/09/08 08:04 AM Re: Hairline cracks in foundation [Re: CR2]
SouthTexGopher Offline
Junior Member

Registered: 06/07/08
Posts: 2
OK - that's a relief. There's no water infiltration, so I'll stop freaking out.

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