Of everything poured on a property, the drive is the one a two-ton wheel tracks over in the same two lines every day, so what lies beneath counts for more than what is troweled on top. Under the flat half of the city the survey returns San Emigdio fine sandy loam beneath the colony grid and Metz loamy sand west of that, both of them wash off the Santa Ana, 70 to 85 percent sand against 13 percent clay, at a shrink-swell near 1.2. That ground never heaves. What it takes away is support.
East of that, on the canyon side, the tracts of the 1970s and 1980s were graded pad by pad, cut into the hill with the spoil compacted onto the low side, and their drives run from the garage down a made gradient to the curb. The soil mapped there is Alo clay at 48 percent clay, shrink-swell 9.3. Those tracts went in between 1970 and 1989, so a hillside drive still on its first slab is 40 to 55 years old, and a slab that age has usually outlived whatever base was rolled under it.
Katella Anaheim Concrete has been pouring here since 2016 under CSLB C-8, carried in Omar Espinoza's own name, with liability insurance on every job. A driveway sitting 30 inches or less above the grade beside it, over no basement or story below, is on the Residential Code's exempt list, which covers nearly every frontage in this city. Behind the finished slab stands a written workmanship guarantee against defects in how it was built.