Foundation repair contractors in Tarrant County

Tarrant is the most geologically divided county in the Dallas–Fort Worth area, and that single fact drives most of what happens to foundations here. The published soil survey states that "four land resource areas are within Tarrant County. They are the West Cross Timbers, Grand Prairie, East Cross Timbers, and Blackland Prairie Resource Areas" (Soil Survey of Tarrant County). Two of those four are named there by their outcrop: the East Cross Timbers "is on the Woodbine outcrop and typically is low hills, reddish sandy soils," while the Blackland Prairie "is an outcrop of Eagle Ford Shale… The soils are highly plastic" (same survey).

So there is no single Tarrant County answer. Sandy Woodbine ground in the northeast and east behaves nothing like Eagle Ford clay in the southeast, and the Grand Prairie limestone-and-clay belt in between behaves differently again.

The mapped share of the county

The county's largest general soil map unit is Crosstell-Gasil-Rader at 23 percent, followed by Sanger-Purves-Slidell at 21 percent, Aledo-Bolar-Sanger at 20 percent and Houston Black-Navo-Heiden at 12 percent (same survey). The clay-dominated units are a minority of the land area, which is why blanket claims about "Fort Worth soil" are unreliable.

Plasticity, as the survey reports it

The engineering tables give plasticity index ranges of 28 to 42 for Houston Black, Heiden, Ferris and Slidell, 20 to 36 for Sanger, 20 to 35 for Navo, 15 to 25 for Crosstell and 4 to 14 for Silawa. Shrink-swell is classed as high above 6 percent volume change and very high above 9 percent, and the survey warns that where the rating is moderate to very high, "shrinking and swelling can cause damage to buildings, roads, and other structures… Special design is often needed" (same survey).

Practical consequence: in Tarrant County the useful unit of analysis is the lot, not the county or even the city. An engineer's soil data for the specific address beats any regional generalisation.

Permit requirements, inspection steps and watering restrictions differ city by city across Tarrant. Those details live on the city pages.