Is it safe to buy a house with sinkhole foundation repair?
Wednesday, July 31, 2019
While it is possible for further sinkhole development to cause problems with a house that has had foundation repair, it is extremely unlikely for two reasons:
- When the foundation is “pinned,” it means steel rods are driven into the ground next to the wall around the perimeter of the home until “refusal” at solid rock, then a bracket several feet long is attached to the rod and fitted under the foundation (as shown below) and tightened, to provide support. The pinning can only fail if the rock under the pin fails.
- Concrete grouting under the floor slab is also part of the specifications for virtually all sinkhole foundation repairs. This fills voids under the center of the home and, again, only very significant collapse (not minor settling) of the soil under the home would cause a new problem.
But how possible is it, really? We asked Michael Driscoll, a structural engineer that specifies 300 or more foundation repairs a year, and he could only think of one repair that had further problems. It was for a homeowner that dismissed the contractor before the work was complete. But an engineer cannot predict with certainty that the house will not have problems in the future if the underlying condition that caused the original settlement progresses further.
So it’s important to verify that all the work specified in the engineering report was actually done. Pinning without grouting under the slab, for example, can lead to problems later. You should get a copy of the engineer’s report, and talk with the foundation company that did the repair. They are usually happy to review the details of their work with you.
It is our opinion that a house that has had foundation repair is less likely to have a future sinkhole problem than the neighboring houses that have not been repaired. We recommend reading our blog post Should I buy a house that has had foundation repair? for strategies to ensure you are getting an adequately repaired house. Also, see How does a repaired sink hole under a house affect its market value?
• • • • • • • • • • • • • • • • • • • • • • • •
Here’s links to a collection of our other blog posts about SINKHOLES:
How To Look At A House
McGarry and Madsen's home inspection blog for buyers of
site-built, mobile/manfuactued and modular homes
for Links to Collections
of Blog Posts