dug out crawl space.

No pics yet. I inspected a house built into a steep hill today. This made the crawl space about 12 feet at its highest point moving to 3 feet at the front. Owner at dug some of it out (at the high side) and cut the earth to within 2-3 feet of cement block support piers. No problems noted other then the digging out. My concern is this. Is there an issue with the piers not having as much earth around them as when they were originally built. Here in NC they go down about 18-24 inches for footings for piers. Would you always have an structural enginner look at this kind of issue regardless. First time I have seen this.

Kenneth, The supporting soil is called the “Cone of Compression” and radiates out at a 45 degree angle from the bottom edges of the foundation. If they interrupt the cone of compression they have compromised the ability of the soil to carry the weight of the structure above and the area compromised will need to be stabilized. The cure should be spec’d by a structural engineer.

I concur with Kenton. I’ve come across this once where the owner “dug out” the crawl space up to and vertical to the foundation wall footings. In my inspection report I stated the little to no angle of repose (con of compression) of the soil at the footings could undermine the stability of the structure with a possible loss of foundation integrity if the soil should sift, or erode under the footings. Obviously I recommended further review by a qualified foundation specialist or structural engineer for determination, repair options and cost.


Cmon Pete, admit it. You got your butt wedged under a beam and had to dig your way out. :mrgreen:

Stephen, Damn it I was feeling all smart!!! :mrgreen:

In fact Pete, I found this drawing done by your client.

As previously stated, the angle of repose is the key here. However, it is not always 45 degress. 45 degrees is just a rough guideline. It depends greatly on the type of soil. ie. A sandier soil will have a smaller degree than a soil with a lot of clay. This is what the engineers get paid for.

Since the home is built on the side of a hill, the engineer will also be considering what is required for support of the uphill soil, as well as the foundation. That is why many homes built on a hillside have a half basement, rather than a full basement.

Jim King

…and also why occasionally a home slides down the hill.

I know where you live Stephen,… sleep with one eye open brother,… lol :mrgreen:

Education and Humor, can’t beat that anywhere. Thanks for the info and the laughs guys. Ken.