Thanks Laura and everyone for the help! After multiple quotes, some great advice here, and an engineer inspection, we decided to repair the foundation with an external pier system. Here is our rationale, in case anyone else encounters a similar problem.
- In our Georgia home, when it was new the warranty would have covered settling up to 1/4 inch. That ours is 3/4 inch out suggested settling since the warranty passed and/or a serious enough issue to remedy.
- Drainage patterns and erosion around the foundation were consistent with the settling we saw, suggesting the slab foundation had been continuously undermined throughout the 23-year life of the house.
- We plan on holding the property as a long-term rental, and the amortized cost of the repairs is marginal. The house will continue to be an excellent investment.
What we learned: We got lucky that we gained a lot of extra equity soon after we bought the house, which makes these repairs palatable. When buying the house, we made the mistake of getting an inspector recommended by our realtor who seemed credible and detail-oriented but I think just wanted to get us into the house. Whilst there were no obvious structural issues caused by the settling, the evidence was there for a trained and impartial eye to see. In addition, I will also be paying much closer attention to water flow patterns and signs of erosion around our next investment!