Replies

1. 
   Guest_ | Feb 05, 1999 07:42am | #1

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   Joseph,
   The first thing to figure out is if this settling is still happening or not. Sometimes right after a house is built, it will settle a little bit, showing the cracks you describe. Once it's done settling, if there are no other problems, the house can be stable and sound. These kinds of cracks are not usually a problem. If this is the case, there are several ways you could go, none of which are very difficult or expensive.

   Then, sometimes you get houses that aren't so stable. This can happen for a variety of reasons.
   So, let's try to figure this one out. How big are the cracks (width of crack and length relative to the wall)? How long have they been there? How long have you owned the house? How old is the house? Do the cracks open or close seasonally? What climate are you in? Is your house built on expansive soils? Clay? What kind of soils? How is the drainage on your site? How is the grade at the foundation wall? Any water build up at the walls? Any efflorescence showing? What kinds of loads are imposed on the block wall? The stem wall? Any unusual point loads? Is any of what you're describing sub-grade i.e. basement or retaining wall?

   Now I'm curious, too.

2. 
   figuers | Feb 06, 1999 10:15am | #2

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   there is nothing you can do to the above ground part of your house to stop/slow down the differential movement of your house. The horizontal crack at the top of the stem wall sounds like slight outward rotation of the stem wall (assuming you refer to a shallow perimeter footing). About the only way to stop the movement of the house is to replace the foundation or add additional supports to the foundation. The distress is caused by movment of the soils supporting the foundation. This can be the result of seasonal movement of expansive clays, hillside soil creep, landslide, or differential settlement of a cut and fill pad (the cut part of the pad does not move, but the fill part settles). shallow or deep foundations can be replaced or have supports sistered to them (beware of pipe piles). If you have a slab-on-grade, there is a new technique that may help. This is injection of foam into the soils. it will relevel the house and provide additional support. the other key thing to do is exterior water control. Surface waters( downspouts, surface runoff, etc) should be kept at least 10 feet away from the perimeter of the house. If the house is in the range of 20 years old and the movement was caused by settlement of fills, then it is possible that settlement has essentially stopped and you can patch and paint. if the movement is caused by soil creep/landsliding or by exansive soils, then foundation repair/upgrade is about the only option. the damage can also be caused by trees. make sure large trees are at least 10 feet away from your house.

1. 
   Joseph_Cole | Feb 10, 1999 07:46am | #3

   *Thanks Dave for the responce. An engineer said the cracking is do to movement of the soils below and adjacent to the stem and footing. The present slope of the yard is not conducive to quick runoff and the soil has developed a valley against the stem which helps channel and hold moisture against the stem. The cracking on the stem varies in width from so small you can't get a knife blade in up to a 1/4 inche. I have tapped on the area and some places sound hollow. The engineer recommended a polymer resin based patch material called Sitka 123 that has very high compressive strengths but I wondering if there is a less costly material ($60 per 2 cf box) that may serve the same purpose. I'm not looking to poor-boy this since it will affect resale, but I also do not want to rival Rockefeller is expenses. Anything would help. Oh, the house is 30 yrs. old, and is in the Phoenix AZ area.

3. 
   Joseph_Cole | Feb 10, 1999 07:46am | #4

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   I have differential settling in my house that is showing itself through stair step cracking in the block walls and horizontal cracking in the stem wall. Is there a concrete/bonder mix that will stop the settling or are things going to get REAL expensive?