Poorly Supported Pier

[Fred Duemig]

Sorry, the pictures are a little close up. This is an inspection of an extension of a house with a small basement that apparently was dug alongside an existing dirt floor crawl space. It appears as if the original intent was to extend the basement a little further into the crawl than they did, however, they stopped. Alongside the foundation wall separating the crawl space from the basement is a gaping hole, probably 6' deep and about 8' in diameter. There is an existing pier about 10" from the edge. It also appears that one of the piers was removed; however, it seems the new foundation wall (basement) would negate the need for that pier. The hole in itself does not seem to be a major problem, however, my concern is the pier resting on the edge of that hole. If the dirt shifts or breaks down, so does that pier. Any thoughts?

Fred

[Richard A. Hetzel]

Depends how deep the footing is under the pier. If the excavation is within the 45-degree plane extending out and down from the bottom edge of the footing, then it can be assumed that there is the possibility of movement, In certain soils, that angle can be steeper, but as a rule of thumb, the 45-degree plane should govern.

[Kenton H. Shepard, CMI]

...what Richard said. Otherwise known as "compromising the cone of compression".