Expansive clay around Milpitas
Newpark soil, 30% clay, lep=4.5, which is moderate shrink-swell.
Newpark soil, 30% clay, lep=4.5, which is moderate shrink-swell
Soil sampled near Milpitas runs 30 percent clay with a linear extensibility of 4.5, which is the standard measure of how much that ground changes volume with moisture.
Why this matters for a footing
A footing is designed for a soil that stays roughly the same size. When the ground beneath one part of the house changes volume and the ground beneath another part does not, the house is asked to bridge the difference, and concrete is not good at that.
The median home in Milpitas was built in 1987, which sets what the footing is likely to be and how deep it sits.
What you can do without spending much
- Get roof water away from the wall - extensions on downspouts are the cheapest intervention there is
- Keep the soil moisture around the perimeter even rather than swinging wet to bone dry
- Watch tree roots close to the footing, which draw moisture out of one side only
- Mark and date crack ends, then photograph them each season
Milpitas averages 537 mm of rain a year, and it is the swing between the wet and dry parts of that total, not the total itself, that moves a footing.
Prices in nearby cities
Antioch · Bellflower · Brentwood · Buena Park · Castro Valley · Concord · Downey · El Monte · Garden Grove · Hawthorne · Hayward · Inglewood