Sink hole under driveway/retaining wall.

by T D
Boy, do I need help with this one. The house is 27 years old and the crack in this section of the driveway has gotten worse and sinking. Now the 3' concrete retaining wall is starting to fall. I strongly suspect builder trash being buried here. Suggestions?
  6 answers
  • 360 Sod (Donna Dixson) 360 Sod (Donna Dixson) on Oct 29, 2012
    Yikes TD. The only viable option to waiting until it becomes impassible is to take out the sections of wall and driveway, add fill dirt and replace. It might be less expensive than you think.
  • KMS Woodworks KMS Woodworks on Oct 30, 2012
    builder trash (wood possibly) combined with poor back fill compaction. buried solid trash is not normally a problem if is compacted. concrete and rocks will not shrink. It is the loose filled soil around them that does. Earlier this year when working on my driveway retaining wall I discovered an entire engine block. Needless to say I left it there.
  • Only fix is to dig it up and repair, Not uncommon for as KMS said to be builders trash, but it can also be natural settlement from where perhaps an old tree was located, or perhaps roots from a nearby tree that have decayed. IN any case it will need to be dug up, a new footing for the curb installed, then properly back-filled, compacted and then rebuilt. In any case it will get worse as more water is allowed to flow into the low spots and collect. This will cause faster erosion of the soils and more settlement of the area.
  • Elizabeth Dwyer Simpson Elizabeth Dwyer Simpson on Feb 22, 2014
    Thank you for sharing this. I have a much smaller problem in a side walk along side my house. I, of course, had no idea how to deal with it. Now I know where to begin.
  • RI Waterman RI Waterman on May 28, 2015
    Typically this is indicative of a a broken water or sewer or drain pipe. A crack in a sewer or drain pipe causes the surrounding soil to be drawn into the pipe creating a void around the pipe and then slow or sudden collapse of the soil and/or structures above. If you have a sewer or drain pipe in this area it could be the cause. A leaky water pipe also can wash the soil away. have your pipes checked.
  • Stewbie Stewbie on Jun 22, 2016
    Look in the Yellow Pages for a concrete contractor or a paving contractor that does what is know as Hydraulic Jacking. The can pump sand or concrete mixes under pressure to a point where the drive and wall will be a lot better. But ... and I say BUT that may be a temporary fix. Opening up the slabs will tell you if it's a rotting old tree stump they built over (maybe a 10-15 year development problem); a broken sewer or drain line (often 3-5 year problem); or construction debris (this last one is frequently visible in 7-9 years). If it were me, I'd open up and clean it out. But hydraulic jacking has proven itself to me as a viable alternative.