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define "undisturbed ground surface"

Discussion in 'Residential Foundation Codes' started by BSSTG, Jan 8, 2010.

  1. BSSTG

    BSSTG Gold Member

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    per 06 IRC 403.1.4. footings shall be placed 1 ft into undisturbed ground surface. So if a developer puts a foot or 2 of fill on his property, and it is leveled and such and sits for 6 mos. or so, would you consider that undisturbed ground surface?.....To me undisturbed ground surface would be natural grade without any fill. Any fill added with the intent of having a building on it should be approved by an engineer after having done soils tests etc.

    thanks

    Byron
     
  2. fatboy

    fatboy Administrator

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    Re: define "undisturbed ground surface"

    I agree with you. I would require an engineers report/compaction test. I asked an engineer once how long soil had to be in place to be considered undisturbed, he didn't have an answer other than, how long has the natural, native soil been in place?

    I wouldn't buy two years without an engineers report/compaction test. JMHO
     
  3. Builder Bob

    Builder Bob Sawhorse

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    Re: define "undisturbed ground surface"

    IMHO, that doesn't qualify.....I know while working for the DOT on a interstate route, they did preliminary grading for the interstate and left it in place for almost three years - When the dirt stats growing grass, shrubs, and the trees start becoming 4 to 6 " caliper -I believe the soil has been their long enough to be considered undistrurbed.

    In other words, it starts to look like the rest of the grasslands and fields around it....and cannot be distinguished as being "recently" deposited.
     
  4. Paul Sweet

    Paul Sweet Sawhorse

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    Re: define "undisturbed ground surface"

    It depends how the fill was placed. If it was suitable soil placed in lifts and properly compacted and tested, then it could be considered undisturbed. If it was just loosely dumped and leveled, then I would wait a millenium or so before considering it undisturbed.
     
  5. FredK

    FredK Gold Member

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    Re: define "undisturbed ground surface"

    It's not and I always requested compaction report when doing a field inspection of a site that has fill.
     
  6. north star

    north star Sawhorse

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    Re: define "undisturbed ground surface"

    Byron,

    As others have already stated, the amount of time that the soil is there is not the relavant factor.

    A soil compaction test is what is required. If the soils are there for XX amount of time and they

    are still insufficient to carry the proposed imposed loads, then they will either have to be removed

    and replaced or altered to sustain the loads that will be placed upon them.

    BTW, welcome to our new & "much improved" home! MEGA props go out to Jeff Remas for

    stepping up and providing us with a very user friendly site. ;)

     

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