Davis sits on Yolo County clay. The neighborhoods west of Highway 113 — Old North, Old East, Central, Davis Manor — have 1948–1972 ranches over slab or shallow pier-and-beam, almost all needing some form of encapsulation by year 50. East-side newer construction (Mace Ranch, Wildhorse, Stonegate) has fewer crawl-space issues but more drainage complaints during wet winters. Network specialists know every Davis neighborhood's quirks.
An on-site assessment: moisture meter, structural-visual, and a written scope you can act on.