Are there soil requirements for substrate of monolithic

by Pat Delaney
(Matthews NC)


We have a monolithic slab that cracked and there is displacement on one portion of 1 inch. We had a soil engineer check the substrate and they found heavy organisms in soil under the slab. Was the builder suppose to meet certain requirements? End result, we have lots of ceiling and wall cracks and uneven door jams.

Hi Pat, I am very sorry about the damages to your floor slab and house.

Slab damages (whether monolithically poured or not) due to ground settlements are very difficult to resolve. If there are provable evidences that the contractor was negligent then the contractor can be held liable. It is extremely difficult to prove that the contractor knowingly build the slab/house foundations over the “heavy organisms” that the soil engineer found.

Due to financial reasons, vast majority of residential construction are done without the professional services of soil engineers. Geotechnical engineer is another name for soil engineers - they are responsible for investigating by testing the soil to determine the type of foundations necessary for a particular soil type.

This soil testing includes retrieving soil samples from certain depth that may vary from a few feet to hundreds of feet beneath the surface. Should this step was done previous to the construction, the “heavy organisms” may had been discovered prior to the construction and necessary action could had been taken to alleviate the problem.

A normal contractor is hired to construct a building/house, unless his contract was specifically instructed him to take full responsibilities of the soil, he is not liable.

I had a similar issue some years ago. I mistakenly instructed the excavator to dig the basement for a custom home to be 10ft below the street curb. As a result, the hole was dug 4 feet deeper than it should have been. Thankfully for the mistake, we dug up trash that was buried by the developer.

What we discovered in this incident helped explain the complaints from residents that had experienced foundation settlement in the sub-division.

Something to look into is city records to see if your lot was used as a dump in the past and the developer or city failed to disclose this info to the prospective residents.

Best of luck

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