Foundation repair salespeople should not analyze, or make recommendations for rectifying foundation problems.
I often discuss in previous blogs how foundation repair salespeople should not analyze, or make recommendations for rectifying foundation problems. I go into why in great detail. Today, I want to share a visual example of that type of foundation repair failure.
We were asked to come up with a repair plan for a home built on a hillside in Northern Arizona. As is often found on these types of homes, the original engineering (or perhaps lack thereof) and construction was inadequate. The result is depicted below.
The columns that supported the home were made of 8x8x16 masonry block that was badly leaning. It exhibited what engineers call a ‘slenderness problem’, which in simple terms means it was too tall or skinny and that left it vulnerable to tilting or buckling…. Especially when the soils start to shift and there are lateral loads from a steep slope.
The block columns supporting the structure were built the wrong direction to resist overturning. If the block column would have been turned 90 degrees, it would have been much sturdier and more likely to resist over turning or buckling.
After analyzing the situation, our engineers realized that the situation was precarious. They suggested that not only were the masonry columns sinking, they were laterally shifting and leaning on a very steep hillside. They proposed an ingenious solution that utilized the deep soil bearing solution of a push pile coupled with the lateral stability of a concrete column and footing.
The client did not appreciate the engineering expertise nor the innovative approach. They contacted another foundation repair contractor, who proposed a solution as follows.
Their solution was developed and “designed” by a foundation repair salesman with no engineering expertise. The solutions consisted of installing a small diameter steel post to sit on top of a push or helical pile. This is a crazy solution! The small diameter steel post would return back to what engineers refer to as a “slenderness problem” that was worse than the original slenderness of the improperly constructed masonry column. It lacked fixity at the base and also was likely to fail in buckling. This solution would have failed either during or shortly after installation, resulting in the entire house falling down the hill!
The foundation repair salesmen didn’t know what they didn’t know. It’s a perfect example that illustrates why non engineers should not be analyzing existing structures for dysfunction nor designing structural repairs to remedy the situation.
