Terravane Soil & Foundation · Yellowlake Country & Bluejoint Flats · Expansive-soil specialists since 2008
In clay country, the soil moves first. The house just follows.
Yellowlake sits on some of the most expansive clay in the state — soil that swells when you water it and shrinks when you stop, taking the slab along for both rides. Terravane starts below the house: a bore and a plasticity index for your actual lot, a moisture program to keep the ground quiet, and piers only when the readings insist. The soil is the client — the house just benefits.
You cannot fight clay with concrete. You can only keep it company — water it like a crop, shade it like a temperamental relative, and pierce past it when it refuses to be reasonable.
The test
A bore to eight feet, the sample read for plasticity index and swell pressure, and a map of what your lot is actually doing — active zone, drainage paths, the trees pumping the ground dry every August. Every recommendation we make traces to a number on that report, and you own the report.
The moisture program
A buried soaker line on a timer at the drip edge, four probes at the corners, and a calendar that wets the active zone evenly all season — because clay does not want more water, it wants the same water everywhere. Three quarters of the lots we read hold their level on the program alone, no piers, and the probes prove it twice a year.
The pier program
Resistance piers driven past the active zone to stable strata, bracketed to the footing and load-tested as installed — for the slabs and walls the readings say will never hold their level on water management alone. Installed only where the map insists, priced per pier, logged per pier.
Test, water, pier — in that order
The program sheet
Nothing on this sheet is sold without the number that justifies it: no soaker line without a bore, no pier without a season of probe readings, no re-level without a map. The lines stack in the order the lot asks for them — and three lots in four never reach the bottom of the sheet.
Terravane sheet — 2026 season
Soil bore & PI report$520 flat
Bore to 8 ft, plasticity and swell read, lot map with active zone and root survey
Perimeter soaker network$2,600 installed
Buried line on a timer at the drip edge, zone by zone, wetting the active zone evenly
Moisture sensors & seasonal reads$340 / year
Four probes at the corners, read in spring and fall — the graph your house has never had
Root barrier, 40-mil HDPE$22 / lin ft
Trenched to 4 ft between the trees and the wall — the sixty-foot argument, ended
Resistance pier, installed & load-tested$1,940 each
Driven past the active zone to refusal, bracketed, logged — pier by pier, in the report
Slab re-level, mud or foamfrom $3,800
For slabs the map says floated alone — lifted, void-filled, and enrolled in the program after
How it goes
The clay calendar
The same sequence on every job — the only variable is your project.
March
The read
Probes read, last year’s cracks photographed against this year’s, the bore refreshed where the lot map says. Every program on the street starts with the same document, and the document starts with what March did.
June
Soak before it splits
The soaker network comes on before the heat does — a slow, even wetting of the active zone, because clay that dries in July shrinks, and clay that shrinks takes the middle of your slab with it. The timer does the work; the discipline is starting early.
August
Peak suction
The trees drink the lot dry from the top while the sun bakes it from the side. This is the month the sensors earn their keep — a corner reading low gets its zone opened, a week before the drywall would have said so instead.
October
The re-wet
Rains return and the program tapers — evenly, on purpose, because a swamp is as bad as a drought to a slab. The fall read lands in your file beside the spring one, and the graph gets its second point.
January
The quiet season
Frozen ground moves little and lies less. Piers, barriers and slab work are scheduled here when the lot allows — the season the soil stops arguing and the crews can hear the house.
The level year
Stay in the program twelve months — sensors read, soakers kept, the calendar followed — and your slab moves anyway: the re-level is credited against every dollar of the program you paid. We cannot promise the soil will behave. We can promise the arithmetic will.
Why a program, not a fix
Because concrete loses this argument. Clay moves every season, with or without permission, and a one-time repair on moving ground is a subscription you pay in cracks. The program keeps the water even, the readings honest and the warranty earned — and when the readings do insist on piers, the piers land on a lot that will stop fighting them.
Yellowlake Country & Bluejoint Flats, 2024 — 2026
Lots from the ledger
Six lots from last season’s ledger, each captioned with the number that decided it. The soil wrote these captions; we just keep the file.
Two outfits quoted me piers off a walk-around — eleven and nine. Terravane bored the lot, read PI 44, put in a soaker line and a root barrier for the willow, and the cracks that opened every July have not opened in three. Total cost was a third of a pier job, and I get a graph every fall that I actually understand.
The piers were honest work — nine of them, load-tested, logged, on the side of the house the readings named and nowhere else. What sold me was the calendar that came after: the program keeps the rest of the lot quiet so the piers stay lonely. Two October reads later, the graph is a flat line and I frame it like a diploma.
Why not just water the yard more?
Because clay does not want more water — it wants the same water, everywhere, always. A hose at the corner on Sundays swells one corner and leaves the rest shrinking, which is a slab-farming technique, not a maintenance one. The buried soaker network waters evenly on a timer at the drip edge, and the probes tell it when corners disagree. Even is the whole game.
Do the trees really matter that much?
On our lots, they are usually the first suspect: a mature willow pulls water through roots that reach sixty feet, drying the active zone under the house on one side only. The barrier trenches HDPE to four feet between the tree and the wall and ends the argument. Remove-the-tree is the nuclear option; the barrier keeps the shade and stops the thirst.
Will my insurance cover any of this?
Almost never for movement — graders classify it as earth settlement and exclude it. What the report does buy you is clarity at sale time and, occasionally, a builder claim when the house is young and the bore shows the lot was never prepared to code. We write everything to be evidence; where evidence has a payout, you will have the documents.
How do you know where piers are needed?
The bore gives the soil, the probes give the season, the elevation survey gives the shape — and piers go where all three agree. That is why 814 lots read last season produced 212 piers: the pier program is for the lots that cannot be managed, not the lots that can be sold. Every pier position arrives with its reading attached, and you can audit every one.
We are building new on clay. Too early to call?
The best call you could make. A bore before the foundation is drawn changes the whole design — pier and grade beam where the plat index demands it, or conditioned slab and drainage where it does not. Builders here know our reports because their engineers ask for them; the $520 you spend before the dig is the cheapest insurance a Yellowlake house can buy.
The field line
Bores run year-round; the phone is answered by someone who has read one. Bring your cracks, your trees and your July doors — the report comes first and the program second, never the other way around.
74% of the lots we read never need a pier — but every lot gets the same honest reading · (555) 045-1638 · soil@terravane.example
Start with the bore
Town, rough age of the house, and whether the cracks take a season. The $520 bore and PI report is your document — every line on the program sheet traces to a number in it, and no pier is ever quoted off a walk-around. soil@terravane.example