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Old 03-06-2013, 12:14 PM   #16
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Foundation crack


House was built in 1999. Contractor says the soil in the area causes these cracks and he sees them all the time. Crack was there when I bought the house 2.5 years ago but recently its been pointed out to me on several occasions. He recommended using concrete in a tube or something to patch up the crack. Ill do as he suggested with the 3 2x8s on block columns on top of 2' concrete footings. Then patch the crack and be done with it. Ill probably go around the foundation under the house and look for more cracks also.

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Old 03-06-2013, 04:09 PM   #17
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Foundation crack


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Contractor says the soil in the area causes these cracks and he sees them all the time.
Ask him how the soil causes this? Some contractors say anything.
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Old 03-06-2013, 04:51 PM   #18
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Foundation crack


He said they use some cheap kind of dirt to replace the dirt that was there before excavating when building begins instead of back filling with original dirt. Not sure why this would be done but its the same dirt all around the house.


Edit: thinking about it now. I don't know if it was the contractor who told me that or not. Maybe the builder said that. The contractor did day it was very common and not a major issue which is good to know.

Last edited by nikeman; 03-06-2013 at 05:18 PM.
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Old 03-06-2013, 05:08 PM   #19
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Foundation crack


Never heard of that one!
Can't see what difference backfilling with 'cheap' dirt makes.
What's the structural difference between cheap dirt and premium dirt?!
It's normal shrinkage cracking - nothing more.
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Old 03-06-2013, 06:18 PM   #20
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Foundation crack


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Never heard of that one!
Can't see what difference backfilling with 'cheap' dirt makes.
What's the structural difference between cheap dirt and premium dirt?!
It's normal shrinkage cracking - nothing more.
That's good. Would you guys just patch the crack and let it be or do as recommended and dig the 2 footings and 2 concrete columns?
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Old 03-06-2013, 06:20 PM   #21
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Foundation crack


I do believe that person was talking out their hindquarters. You will never convince me that trucking dirt out, and trucking different dirt in, would be more cost effective than just leaving the same dirt there. All fill dirt is cheap. Diesel is not.
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Old 03-06-2013, 06:33 PM   #22
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Foundation crack


Like I said, I may be confusing the contractor with the builder. The builder is the one who told me about the different dirt. I talk to so many people on a daily basis sometimes I blend conversations together.
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Old 03-06-2013, 09:34 PM   #23
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Foundation crack


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Jomama; those pics don't suggest uneven foundation settlement because the crack looks fairly even in width.


I never mentioned anything about settlement, maybe you did??? I did, however, note that there's likely some sort of deflection, or bowing, in the wall, which would likely be in line with what the contractor who visited the site noticed...

All concrete block walls undergo shrinkage though, as you imply, with softer mortars it will not be immediately apparent. The shrinkage will still be there, but it will be more evenly distributed by several hairline cracks, rather than one wide one. It's also worse if the blocks were too wet when layed.

Modern CMU's here in the state's are cast at a zero slump, and often get sent through a kiln. They then usually sit in a yard fro a few weeks minimum. Highly unlikely that they'd be "green" if that is indeed what you mean by "wet". I can still tell you that it's highly unusual for the block itself to crack rather than the far more typical step cracks through the mortar itself. It's simply elementary masonry basics, the binder/mortar around the masonry unit should always be weaker than the unit itself.

OP doesn't say how old the house is, but that the crack has been like that at least 2 1/2 years. My guess is that it happened soon after the house was built. If the contractor says its a common problem around there, then maybe its the local type of block; surely all the houses round there won't have identical foundation movement?

It's an aesthetic/weatherproof problem and the crack just needs filling. A crack like that won't make the bathroom floor uneven - that's probably just a coincidence.
http://www.aggregate.com/Documents/T...cal-Manual.pdf page 31.
Nikeman, I don't find it to be a far stretch when a contractor tells you that inferior soil was placed around the foundation as backfill. Many soils will hold moisture, freeze in the winter, and put an excessive amount of lateral pressure on the foundation in winter/early spring, causing similar issues. If this phenomenon didn't occur, I'd likely have to find a new profession, as I field alot of calls for similar issues this time of year.............
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Old 03-07-2013, 10:12 AM   #24
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Foundation crack


Jomama;
All cmu's shrink after manufacture, no matter where or how they're made.
(and AAC blocks are the worst in this respect).
I don't doubt that 99% of homes with foundation walls of concrete block don't have movement joints, but any wall above 20 - 30ft long will be subject to cracking.
If the mortar is softer than the block (which of course it should be) the cracks will be distributed and fine, so not often noticeable, but they're there all the same. If the mortar is too strong, there will inevitably be one large crack, as the OP has.

All CMU walls, whether in the US or Timbuktu, suffer shrinkage cracking. It's just that house builders don't bother with joints because they are an additional cost, and have to be accommodated through the rendering etc.
OP should just inject filler into the crack and forget about it.

As for the dirt - builders/contractors the world over will tell you anything about anything, and what they don't know they'll make up.http://www.masonrymagazine.com/12-02/controljoints.html
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Old 03-07-2013, 09:27 PM   #25
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Jomama;
All cmu's shrink after manufacture, no matter where or how they're made.
(and AAC blocks are the worst in this respect).
I don't doubt that 99% of homes with foundation walls of concrete block don't have movement joints, but any wall above 20 - 30ft long will be subject to cracking.
If the mortar is softer than the block (which of course it should be) the cracks will be distributed and fine, so not often noticeable, but they're there all the same. If the mortar is too strong, there will inevitably be one large crack, as the OP has.

All CMU walls, whether in the US or Timbuktu, suffer shrinkage cracking. It's just that house builders don't bother with joints because they are an additional cost, and have to be accommodated through the rendering etc.
OP should just inject filler into the crack and forget about it.

As for the dirt - builders/contractors the world over will tell you anything about anything, and what they don't know they'll make up.http://www.masonrymagazine.com/12-02/controljoints.html

A) CMU's rarely shrink here enough to cause a crack similar to what has been posted. The block is bar far the most stable element of the assembly.

B) The link you posted is predomintly about clay veneer brick, not structural CMU.............
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Old 03-08-2013, 07:34 AM   #26
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A) CMU's rarely shrink here enough to cause a crack similar to what has been posted. The block is bar far the most stable element of the assembly.

B) The link you posted is predomintly about clay veneer brick, not structural CMU.............
This is the 3rd paragraph down in that publication, which specifically refrs to CMUs

"Concrete masonry, just like all concrete products, it's the largest volume that it will ever be at the time that it is constructed," says Dennis Gruber, Director of Technical Publications for the National Concrete Masonry Association. "It has moisture in it and as it dries out, it cures, and it shrinks. When it shrinks, it tries to pull the ends in and make the panel smaller. That's alright if it's not restrained, but it's restrained, as the wall is tied in to your foundation, roof and floor members, keeping it from pulling the ends in and from shrinking. This results in cracks, because masonry is much weaker in tension than it is in compression."

here's another one picked at random (US source)
Expansion and Shrinkage of Units

Following manufacture, clay masonry units expand when exposed to moisture. This volumetric change in the unit results in an accumulated growth of the wall system that is irreversible. Concrete masonry units typically shrink following manufacturing. These movements, if not accommodated in the design of the masonry elements, can cause cracking, spalling, and displacements in the masonry. For this reason, expansion joints are required in clay masonry construction, particularly in areas exposed to the exterior in where the units will become wet. Expansion joints are typically required at corners, offsets, and other changes in wall plane; changes in wall construction; and at regular spacings (typically 20 to 30 feet on center maximum, depending on the units). Guidelines for expansion joint design/layout are provided in Brick Industry Association (BIA) Tech Note 18A.
Concrete masonry walls are typically reinforced with joint reinforcement for shrinkage control. Depending on the size and spacing of the reinforcement, the spacing of control joints will vary. However, control joints are required in all concrete masonry walls. Guidelines for control joint placement are provided in National Concrete Masonry Association (NCMA) Tek Note 10-A.

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Old 04-10-2013, 12:57 PM   #27
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Foundation crack


There is another smaller crack on the side of my house that has probably been there but I never noticed before. Under the house on the sides there are extra concrete columns in front of the foundation that support the the beams that run across the entire underside of the house. The crack is right beside the middle column. It doesn't appear that that foundation wall supports much weight so I'm thinking this isn't much to worry about.

Should I add the extra support for the original crack though? If its just a shrinkage crack would it be safe to just patch the crack with concrete or mortar and be done with it?
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Old 04-10-2013, 01:41 PM   #28
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Foundation crack


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There is another smaller crack on the side of my house that has probably been there but I never noticed before.
That's the point; most people don't notice cracks, bulges and leans etc until they're brought to their attention - then they suddenly become worried!

A pic would help but, if it's in the middle of the wall, and the crack is more-or-less vertical, and of consistent width, its far more likely to be normal CMU-wall shrinkage, and nothing to worry about. Just point it up with cement mortar.
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Old 04-10-2013, 02:31 PM   #29
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Foundation crack


Just dig down a little and look at the concrete footing. If it is not cracked it is a shrinkage crack and the step just provided a starting point for the vertical crack, but it would probably have occurred somewhere with a 40' wall.

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Old 04-10-2013, 06:49 PM   #30
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Foundation crack


I would not do anything about that crack except to maybe grind it out a little and gun concrete colored Urethane sealant like Sika NP-1 into the groove. Your so called inspector and contractor are over reacting like nothing I have ever seen before.

As far as the bolts go, I dont know who designed your deck, but you have too many bolts, with flat washers that are too small. You should be through bolting to the foundation, and I would use 5/8 Hot Dipped Bolts with 2 inch thick washers.

Didn't the inspector comment on the bolts? Your plan showed these bolts, and it passed? Just wondered.

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