OLATHE

Olathe went from a county seat to one of the largest cities in Kansas in about thirty years, and most of that happened from the eighties onward. That means a lot of deep basements poured quickly on ground that was scraped, filled and compacted on a builder’s schedule, over Johnson County clay that swells hard after a wet spring.

A poured wall handles that well for fifteen or twenty years. Then the backfill finishes settling, water starts collecting against the outside of the wall instead of draining away from it, and the wall starts taking a load it was not carrying before.

Our own project records cover more than 200 foundation and waterproofing jobs in Olathe, and those records only go back a few years — the real number is higher. Enough of them, either way, that we can usually tell you what we expect to find before anything gets opened up.

What the ground under Olathe is actually doing

The soil survey puts Oska under more of Olathe than any other single soil, with Martin close behind. Both are clay-heavy — Oska runs about 42% clay — and both carry a linear extensibility near 7.6, which is high. Linear extensibility is simply how much a soil grows when it takes on water and shrinks when it dries, and it is the number that decides whether a dry August shows up in your door frames.

What that means in practice: Olathe soil moves enough to matter, but not so much that it moves uniformly. One end of a house can sit on Oska and the other on something considerably calmer, and that difference across a single footprint is what cracks a wall.