Residential structural failures can result from just about any construction oversight, big or small. Improper drainage, active soils, or simply poor design are frequently the culprits. But research shows that, by far, the most common cause of structural failure stems from insufficiently compacted fill material.
With nearly 40 years of data to back up its findings, 2-10 Home Buyers Warranty (HBW) revealed that 80% of all structural failures are due to soil movement beneath the foundation.
“Because fill material is so frequently to blame for structural failures, using it properly is every bit as critical as determining building location, selecting trade partners, and designing an attractive home,” according to Walt Keaveny, risk manager and professional engineer for 2-10 HBW. “If it isn’t sufficiently dense, it can consolidate and cause excessive settlement, which may result in damage to foundations, framing and interior finishes.”
Not only is fill the most common cause of structural failure, it’s also a very costly repair—averaging approximately $50,000 to fix. Pricey, considering how easily it can become compromised.
“Less than a one-foot thickness of improper fill may cause serious distress,” Keaveny says.
Keaveny says to avoid such failures, builders should confirm that the fill meets density requirements by having it tested by a geotechnical engineer. Even when building on land that has existing fill, the home builder is the one who is typically responsible for confirming sufficient density.
An article written by Keaveny and posted on nahb.org goes into further detail about fill placement, moisture, technique and documentation. It also highlights the benefits of working with a geotechnical engineer who can help the builder avoid common problems with compacted fill and safeguard the builder’s accountability.
Read more on the No. 1 Cause of Structural Failures in the White Papers and Articles section of NAHB’s Construction Liability Resources page.
Tags: 2-10 HBW