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Need brains about car plowing into my house

  1. May 8, 2008 #1
    Hello Physicists,

    A drunk driver plowed into my house 6 months ago. The house has been "cosmetically" repaired. Now, I am noticing the cedar siding splitting and separating in the back of the house, directly opposite of where the car hit the wall holding the steel beam. It's a fairly small house.

    Both the contractor and the insurance company have inspected it and said that it couldn't possibly be a residual effect of the speeding car. I disagree. They explained it would have been a dominoe effect and that all the drywall, etc. in between the front hit and the back splits would show some damage. The inside of my house is fine, no cracks.

    I disagree with their explanation. I am thinking of the example of starting a game of croquette, where you support one ball with your foot and place the ball you are serving touching the ball you are stablizing. You smack the supported ball with the mallet which then sends the serving ball on it's way.

    I'm also thinking of the desk toy with the metal balls suspended on wires. You drop the end ball into the line of balls and the one on the opposite end is the one that moves.

    I realize insurance appraisers have their own agenda, to keep claims low. What I would like to know is, in order to take my case to civil court against the driver in order to have the back of my house repaired, do you think it is possible that the damage in the back of the house was most likely caused by the impact of the car? He was travelling between 30-50 mph.

    I would really like your advice on this before I spend $400 to hire a structural engineer to come out and verify it.

    I'm a single Mom on a teacher's salary, and I don't want to get ripped off, but I also don't want to waste $400 if it is not likely caused by the accident.

    Thanks for any and all input!

    GA Tech Mom
  2. jcsd
  3. May 8, 2008 #2


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    Welcome to PF, Ploom.
    While coincidences do happen, I would consider this to be a result of the accident if not proven otherwise. It depends upon the structure of the house, of course, but the "Newton's Cradle" (desk toy) effect that you mentioned would certainly apply to some extent.
    And there should not have been 'cosmetic' repairs done in the first place; it should have been structually rebuilt according to building code. That would entail a full analysis and recommendation by a structural engineer.
    I'm going by Canadian standards here, though, so your results might vary.
  4. May 8, 2008 #3
    In America aswell, they are required to have a structural engineer come out whenever its possible that structural damage has been done. The dynamics of how a house (or any structure) responds to such an impact is incredibly complex, and ends up being governed as much by experience as theory. It is most certainly possible that the impact led to the damage on the other end of the building (your analogies are apt); but from their perspective it is also somewhat dubious if there is no damage in between.
    Let me elaborate on the last part: the reason your examples work (croquette, or newton's cradle) is because of how elastic those objects are. Deformations to their shape are almost instantly righted, transmitting the impact energy straight across.
    Cars, for isntance, are designed to be the opposite - they crumple, there-in absorbing impact (instead of transmitting it to the driver). Generally a house would be more like the crumpling car example, then the perfectly elastic example.
    Still, there are two easy ways the impact energy could have been bestowed on the back of the house. First, some sort of strong rigid support in between (metal beams or the foundation) could transfer the energy; second, a resonant effect dampened the impact in certain regions (the middle of the house) and amplified it at the opposite end.

    In any case; the only person who can really figure it out is a structural engineer - only they have the right experience, and for that reason they should have already been called to examine the situation.
    Insufficient repairs is a huge liability for the insurance company, pointing that out might make them more amenable to doing it right.
    Good luck!
  5. May 8, 2008 #4


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    Good advice so far. It's certainly possible that the damage was caused by the accident, but also possible that it's unrelated.

    If you genuinely believe the accident was the cause of the damage, pay for a proper structural report. I'm concerned that you had 'cosmetic work' done; this would either indicate that you didn't have a structural survey after the accident, or that no structural damage was endured. Either way, because of the time elapsed since the accident, the odds aren't in your favour.
  6. May 8, 2008 #5


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    Aye, the time factor is something that I didn't consider. The accident investigators should have done a full work-up immediately. If they didn't, the constabulary might be just as liable as the driver's insurance company.
  7. May 12, 2008 #6
    Great insights so far. Thanks so much for sharing your input. The time factor probably is a problem here. The contractor, whose specialty is emergency repairs, did climb up in the tiny attic space over the garage which is close to the wall of impact. He eyeballed it and saw no damage.

    lzkelley mentioned that energy could be transferred if there were a solid beam, and the contractor did mention that he hit the wall with the steel truss. I don't know the size or width of this truss and if it would require a direct hit to have any effect, but the driver did catch air over the hump in my driveway as there was a hole in the ceiling porch where his car physically touched it.

    I find it interesting that if you follow the top of the wall that was struck (the one with the steel truss) straight to the back of the house the siding is damaged right at that point where the wall meets the roof.

    On the other hand, my house is covered in cedar siding, and the siding is more prone to damage due to the drying from weather effects. (The weakest link falls). It's the internal structure and effects down the road that I am concerned about. I agree that they should have had a licensed professional do the analysis. I will probably will pay to get a professional out here.

    I'll wait a few more days and see what other replies I get. All great stuff!

    Ga Tech Mom
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