Foundation repair · Caldwell County County, TX
A Caldwell County yard can look like loam and hide 46 percent clay a hand's depth under it, which is where the foundation trouble starts.
Foundation trouble in Caldwell County comes down to which belt the house is on. The northwestern side is Blackland clay that moves hard, with Heiden reaching 17 percent linear extensibility, while the eastern and southern third is Post Oak sand where shrink swell mostly stops being the cause at all. Across the middle sits Crockett, the county's most extensive soil, which reads loamy in the yard and hides 46 percent clay a hand's depth down. Lockhart itself sits on Branyon clay, the series USDA defined from a profile at Martindale about twelve miles up the road.
The ground under Caldwell County County
What the top few inches of a Caldwell County yard hide
The rock under Caldwell County lies in belts that run northeast to southwest, and those beds get younger as you move southeast. That banding is the whole reason one county has two unrelated failure patterns. The northwestern belt is Upper Cretaceous marl and clay, including the Marlbrook Marl of the Navarro Group, and it weathers into the Blackland Prairie vertisols, Heiden, Houston Black, Ferris and Burleson. Next comes the Paleocene Midway Group, a clay and mudstone belt you can confirm on the ground because USDA gives Midway Group mudstone as the parent material for the Behring series, whose type location is at Lytton Springs. Southeast of that the Wilcox Group takes over, roughly 1,200 to 1,300 feet of mudstone with sandstone, lignite and ironstone concretions, and then the Carrizo Sand and the younger Claiborne sands, which is where the Post Oak Savannah soils sit and where shrink swell largely stops being the issue. Two things cut across that layout. The Luling fault zone, the coastward member of the Balcones, Luling and Mexia trend, runs through the county downthrown on the northwest, and along the San Marcos River the faults of the Luling type show a total throw of more than 1,500 feet, which is why the Luling oil field is there at all. Overlying all of it, the Quaternary terraces and floodplains along the San Marcos River and Plum Creek lay down their own clay, carrying Branyon, Tinn, Gowen, Bosque and Uhland. That last part is the one homeowners get backwards. Lockhart sits on terrace clay rather than on residual Blackland, so what is under the courthouse square is river alluvium instead of weathered marl, and it still swells to 13 percent.
Clay you can see at the surface in the northwest
Cretaceous marl and clay weathering into Heiden, Houston Black, Ferris and Burleson. This is full range seasonal movement with no quiet layer near the surface. Heiden holds 50 percent clay from the top down past 147 cm, so the whole soil column works, slab edges drop in a dry summer and lift again in the fall. Steel piers here have to get past the densic material, which Caldwell County restriction data averages at 132 cm.
Loam on top with heavy clay right underneath
A Paleocene clay and mudstone band marked on the ground by the Behring series, established here in 1972. Clay runs 35 to 55 percent and permeability is slow, with slickensides starting as shallow as 8 cm. The moving layer is close to the surface and the soil bottoms out at 102 to 152 cm over densic material, so shallow trouble sits over reachable support.
The terraces along Plum Creek and the San Marcos
Quaternary terrace and floodplain ground carrying Branyon, Tinn, Gowen, Bosque and Uhland, and this is where Lockhart is. Branyon terrace clay swells to 13 percent with slickensides as shallow as 13 cm, so movement starts right under the slab. The lower Tinn bottoms are seasonally wet, and on those sites drainage correction and moisture control usually do more than driving anything.
Post Oak sand in the east and south
Wilcox mudstone giving way to Carrizo Sand and the younger Claiborne sands, mapped as Chaney, Patilo, Silstid, Robco and Arenosa. Linear extensibility runs 1.5 to 4.5 percent, so a foundation problem out here is usually a plumbing leak, poor fill, erosion or undersized footings rather than the clay. Chaney is the exception worth checking, because deep sand over claystone or dense clay behaves the same way Crockett does.
Straight from the soil survey
What the USDA maps under Caldwell County County.
These are the series USDA maps under Caldwell County, ordered by how much ground each one covers. The percentages are shares of the 349,556 acres SSURGO maps for survey area TX055, which is close to but not identical to the county's official area. Linear extensibility is the figure to read first, since it is the percent a soil swells as it takes on water. The last row groups the sandy Post Oak series, which behave alike and are best read together.
| Soil series | Share of county | How much it swells | What that means for a foundation |
|---|---|---|---|
| Crockett | about 61,224 acres of the county's 349,556 mapped acres, roughly 17.5 percent | LEP ≈ 9% | The dangerous one, because it does not look like clay from the yard, with a loamy A horizon from 0 to 20 cm at only 13 to 14 percent clay and 1.0 to 1.5 percent linear extensibility sitting directly on a Btss horizon from 20 to 63 cm at 46 percent clay and 9.0 percent linear extensibility, the Official Series Description putting that abrupt texture change at 18 to 25 cm, 7 to 10 inches down, with densic bedrock at 145 to 203 cm, so the slab is riding on a layer nobody can see from the driveway. |
| Heiden | about 32,079 acres, roughly 9.2 percent | LEP ≈ 17% | The highest shrink swell mapped in the county, running 8.4 to 17 percent linear extensibility by horizon with clay held at 50 percent from the surface down past 147 cm and pedogenic slickensides at 25 to 76 cm, which means the entire soil column under the slab is working every season, and with very slow permeability and densic material at 100 to 165 cm the water only moves in and out at the edges. |
| Branyon | about 26,512 acres, roughly 7.6 percent | LEP ≈ 13% | This is Lockhart's ground, very deep and very slowly permeable clay formed in calcareous clayey alluvium from Pleistocene mudstone on stream terraces, 40 to 60 percent clay with slickensides starting as shallow as 13 cm and linear extensibility reaching 13 percent against a county average near 11.4, so movement begins immediately under the slab and whatever water your gutters do at the corner of the house shows up fast. |
| Tinn | about 16,824 acres, roughly 4.8 percent | LEP ≈ 11% | Bottomland clay along the San Marcos River, Plum Creek and the smaller drainages at 50 percent clay and linear extensibility to 11 percent, on low, seasonally saturated sites where getting water off the lot with grading and french drains usually matters more than anything driven into the ground. |
| Houston Black | about 16,078 acres, roughly 4.6 percent | LEP ≈ 12% | The Texas state soil and the name most homeowners have already heard, very deep at over 203 cm and formed in clayey residuum from calcareous Upper Cretaceous mudstone at 40 to 60 percent clay, with cracks 1.25 to 10 cm wide opening to 30.5 cm or deeper and staying open 90 to 150 cumulative days in most years, which is a long stretch of summer with the support pulled out from under the slab edge. |
| Behring | about 7,510 acres | LEP ≈ 11% | Small in area but it is the series USDA established in Caldwell County in 1972, with its type location at Lytton Springs off FM 1854 near CR 172, formed in loamy and clayey residuum weathered from Midway Group mudstone at 35 to 55 percent clay with slickensides from 8 to 61 cm and soil depth of 102 to 152 cm over densic material at 124 to 203 cm, so the active layer is shallow and slowly permeable while competent ground is not far below it. |
| Chaney, Patilo, Silstid, Robco and Arenosa | Chaney about 23,035 acres, Patilo about 17,898, Silstid about 10,221, Robco about 8,113, Arenosa about 2,351 | low, 1.5 to 4.5 percent linear extensibility | The sandy Post Oak Savannah group over the eastern and southern third of the county, running 1.5 to 4.5 percent linear extensibility with Arenosa down at 2 percent clay, so a failure out here almost always traces to water, fill, erosion or footings rather than shrink swell, with Chaney the one to watch because deep sand over claystone or dense clay is the same duplex trap Crockett sets. |
Linear extensibility (LEP) is the USDA's measure of how much a soil changes volume between wet and dry. Higher numbers move houses.
Where we work in Caldwell County County
The Caldwell County County towns we cover.
Each one has its own page, because the ground changes inside this county and the local pattern is what matters when you are standing in the house.
What gets built here, and when
What we find under houses in Caldwell County
The county carries both foundation types, and the age on the deed tells you less than people expect. Around the Lockhart courthouse square and over in Luling, where the town grew up around the oil field, the older homes are pier and beam over a crawl space, sitting on cedar posts, brick piers or dry stacked stone. On those, the original blocking is often the whole story, rotted, undersized or shimmed by somebody's grandfather, and the soil is a secondary problem. Newer subdivision ground around Lockhart, Martindale, Uhland, Niederwald and Mustang Ridge is mostly slab, and a large share of it went up on Crockett and Branyon, which is the combination that keeps our phone ringing. We do not guess by decade. The inspection reads the slab edge, takes interior elevations, and follows what the water does when it leaves the roof, because an older slab on a lot that drains will outrun a newer one where the ground is flat and the downspouts dump at the corner. On the crawl space houses we are looking at posts, beams, moisture and ventilation before we talk about anything else, and mobile homes get leveled on their own piers rather than treated like a slab.
Permits in Caldwell County County
Who signs off on a foundation repair here.
The first question is who has jurisdiction, and a Caldwell County mailing address does not answer it. Lockhart is the county seat and its own municipality, and Luling, Martindale, Uhland, Niederwald, Mustang Ridge and Maxwell are separate incorporated cities, each running its own permit desk. A house inside a city limit and a house on a county road a mile away are two different processes, even when the mail comes to the same post office. We confirm with the office that actually covers the address before work is scheduled instead of assuming last year's answer still holds, and we pull whatever that office asks for. If a jurisdiction wants a letter from a licensed engineer, that letter comes from an engineer. Our inspectors are ICC certified, we are not engineers, and we tell you that before you hire us rather than after.
Costs, warranty and inspections
The straight numbers in Caldwell County County.
Straight answers
Foundation questions people ask in Caldwell County County.
Now booking free inspections in Central Texas.