Blasting Damage to My House Foundation

Several blasting sessions were done in our neighborhood at a construction site, about 1/4 mile from my house. My close neighbors who were home during weekday blasting sessions felt definite shaking of there houses. When inspecting my foundation (in basement) I found numerous thin cracks along 3 sides of the structure. All above-ground cracks start at the foundation top and "stair-step" down along mortar joints. Our foundation and basement had always been very tight and dry. My wife and I saw no cracks in 11 years of ownership, including accompanying the pest control person in annual foundation inspections. The previous owner certifies there were no foundation cracks or problems whatsoever.
By phone, several repair contractors and people with basic knowledge of blasting all asked if we had any previous cracking, and if new cracks were horizontal or stair-step in appearance. All said stair-step cracking is characteristic of blasting. And,lateral cracking is characteristic of outside soil and water pressure on a foundation.
The measured level of blasting recorded by a small engineering group shows lower levels at their few monitored locations.
This posting is a query to experienced engineering, legal, home-owning, or other people knowledgeable in reference sources. I need documentation for: (1) Stair-step type cracking in foundations being characteristic of blasting. (2) Typical damage appearance from low-level (fringe area) blasting in above and below-ground, previously intact foundations. (3) Good practice requirements for geotechnical surveys before blasting. (4) Good practice requirements for placement and density of seismometers in residential environments. (5) Higher damage probability in certain types of soil, faults and rock formations. (6) Higher damage probability during rainy periods. (7) Other documentation which can help a homeowner understand and realistically deal with this situation. As a very troubled homeowner, I will greatly appreciate consideration and responses from anyone with experience.
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Several blasting sessions were done in our neighborhood at a construction site, about 1/4 mile from my house. My close neighbors who were home during weekday blasting sessions felt definite shaking of there houses. When inspecting my foundation (in basement) I found numerous thin cracks along 3 sides of the structure. All above-ground cracks start at the foundation top and "stair-step" down along mortar joints. Our foundation and basement had always been very tight and dry. My wife and I saw no cracks in 11 years of ownership, including accompanying the pest control person in annual foundation inspections. The previous owner certifies there were no foundation cracks or problems whatsoever.
By phone, several repair contractors and people with basic knowledge of blasting all asked if we had any previous cracking, and if new cracks were horizontal or stair-step in appearance. All said stair-step cracking is characteristic of blasting. And,lateral cracking is characteristic of outside soil and water pressure on a foundation.
The measured level of blasting recorded by a small engineering group shows lower levels at their few monitored locations.
This posting is a query to experienced engineering, legal, home-owning, or other people knowledgeable in reference sources. I need documentation for: (1) Stair-step type cracking in foundations being characteristic of blasting. (2) Typical damage appearance from low-level (fringe area) blasting in above and below-ground, previously intact foundations. (3) Good practice requirements for geotechnical surveys before blasting. (4) Good practice requirements for placement and density of seismometers in residential environments. (5) Higher damage probability in certain types of soil, faults and rock formations. (6) Higher damage probability during rainy periods. (7) Other documentation which can help a homeowner understand and realistically deal with this situation. As a very troubled homeowner, I will greatly appreciate consideration and responses from anyone with experience.
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Contact your homeowners insurance co -- they'll contact the blaster's insurance co, but that's their worry not yours. Also contact your local bldg inspector, fire chief, state fire marshal or whoever has jurisdiction over blasting blasting licenses and blasting permits in your state. It should not be too hard to resolve, but you need to get the ball rolling.

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The Masked Marvel wrote:

I would call your home insurance co right away, and follow up with a CERTIVIED letter their claim department detailing events and previous conditions. Then I'd be real slow to sign off on any kind of settlement - until at least the next 50 year rainfall.
Insurance co's have all kinds of resources available, including forensic meteorologists and, likely, seismologic data. Don't laugh. What are they blowing up? With that kind of close up demolition the news media should be on the story???
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The christian media police? Ha forget it if marijuana is not involved. You need $10,00 cash for a lawyer. The best bet is civil war to rid the homleand of these traitors to the constitution.
Death to the christian military.
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Thank you MM for responding!
The blasting construction project is a 3 story building (approx 25,000 sq ft) located on a hill top which is about 50 ft above ground level of surrounding residences. Some hills in our area have extensive rock formations in them according to folks who built the subdivision. My house is about half way up one such hill.
Your idea of getting the news media involved might be good. A person I talked with who has experience in blasting said companies should always be exceptionally careful and thorough in pre-blast preparations in residential settings. It appears such prep may not have been done here.
Thanks again. I appreciate all information and suggestions, particularly specifics on the subjects in the list in my original post.
research86
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I had a town house near some blasting once. I came home in the middle of the day and there was this guy and girl taking pictures of each complex of 4 homes. At first glance it was a artsy type photo. As I watched the focal point was not on the girl. So I asked what was going on. They were open and honest about it. I guess they did the blasting, I sold the TH some 6 years later, no damage. Never really found out how close the blasting was. I will bet someone will be taking pictures of your area if your close enough for them to worry about it. The TH was slab on grade, on a hill, Block division walls, wood frame and stucco, 2 story.
Do some research, I will bet your in no danger. It takes a lot to get a blasting permit here in AZ and you have to be someone that has a history doing it before they will even consider the permit. Several years ago in downtown Phoenix they dropped the Adams hotel. 1/4 city block square. Dropped in on to itself and just protected the windows on the first through 3 floors. Nary a problem.
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clipped

I didn't suggest getting news media involved. Just expressing surprise that they were not already running some item about it, at least to address 911 calls to report "noise".

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Did you think they would tell you otherwise? Tony D.
<<<<<<<<<<< The measured level of blasting recorded by a small engineering group shows lower levels at their few monitored locations.
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My folks home was 3/4 a block or so from a creek along which they ran a 3 or 4' drainage line. As far as I could tell, they blasted along the whole line. A single horizontal crack appeared in one of the upper 3 rows of concrete block around that time. I actually marked it and it continued to grow. I believe the place was 15 years old, so it wasn't a settling crack which usually appears as a stair-step. Folks sold the place so I don't know if it ever needed repair or not.
Joel. phx

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Thanks for sharing your experience Joel. How have you learned that settling cracks usually appear as a stair-step?
Do you know the look of cracks which usually appear with disturbances from low-level blasting?
Research86

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no insureance company is going to accept it fill em up and flog it off
you will just waste your dough flogging a dead horse

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