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• STRUCTURAL INSPECTION - Foundation Frost Heave
  
  I. Purpose of Investigation:
  
  At the request of the Contractor, a site inspection of recently poured concrete foundation
  walls was made on 6/18/02. Excessive cracking in two locations has become a concern.
  
  II. Description of Structure:
  
  The foundation consists of a residential basement, with an abutting garage foundation.
  8" poured concrete walls bear upon a strip footing. The basement foundation is
  approximately 4 feet below the garage foundation. The overdig required for the
  basement footing removed soil in such a way that the garage footing had to be terminated
  about 2 feet short of the basement wall. This 2 foot gap was bridged with 2x8 timber to
  support the wall concrete during the curing process.
  
  III. Observations:
  
  Excessive cracking was observed at the two locations where the garage and basement
  foundation meet. The crack pattern is consistent with soil heaving forces pushing up
  at the end of the garage footing. (See sketch). Recent weather included temperature
  ranges which could have taken the soil through freeze/thaw cycles. Because the footings
  do not have the typical 42" of frost protection, they are far more vulnerable to heaving
  forces.
  
  IV. Recommendations:
  
  Option #1:
  On each side of the garage, the cracked sections form a small region of wall which
  presumably can be removed and re-poured. The exposed jagged surface is good for
  bonding to the new concrete. It would be advisable to dowel into the existing wall
  with reinforcing bars. A specific design for this can be carried out if requested.
  
  Option #2:
  Pressurized concrete epoxy can be used to fill in the cracks, and bond the concrete back
  together. This should be done only by a contractor with the experience, equipment and
  training needed for this procedure. The epoxy contractor must determine if their
  procedure is suitable for this particular application. If the epoxy procedure is chosen,
  there will still be the problem of an uneven bearing surface at the top of the wall.
  Consideration for grinding this surface level must be made.
  
  For either repair, the exposed conditions leading to heave still exist. It should be
  considered that the same cracking may occur, so long as the air temperature is ranging
  above and below freezing, or the clay soil is swelling due to moisture during the wet
  season. Option #1 has a better chance of success due to the ability of the reinforcing
  bars to hold the concrete together until backfill can be carried out, and permanent frost
  protection is in place.
  
  
  
  

Contact Information

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(517) 467-6145 

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(517) 467-2220

 

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Structural Solutions LLC

8466 Slee Rd.

Onsted, MI 49265

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General Information:     Thomas R. Price, P.E.

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