Foundation repair contractors in Denton County

Denton County is a boundary county. The soil survey places it in three land resource areas at once — "the Blackland Prairie, Cross Timbers, and Grand Prairie land resource areas" — across 958 square miles (Soil Survey of Denton County). The dividing line that matters most for foundations is a geological one.

Sand on one side, shale on the other

The Woodbine Formation "is mainly alternating bands of sandstone, shale, and clay," and the soils formed from it are Birome, Callisburg, Gasil, Konsil and Silstid — sandy and loamy. The Eagle Ford Formation "is primarily shale that underlies the rolling Blackland Prairies of Denton County," and the soils formed from it are Burleson, Crockett, Ferris, Heiden, Houston Black, Navo, Wilson and Vertel. The Austin Group chalk occupies only a small part of the county, producing Eddy and Stephen soils (same survey).

The mapped shares confirm the split is real, not marginal. The sandy Birome-Gasil-Callisburg unit covers about 24 percent of the county, the clayey and loamy Sanger-Somervell unit about 23 percent, and Navo-Wilson about 12 percent (same survey).

What the survey says about movement

Its county-scale conclusion is direct: "Most soils in the county change greatly in volume upon wetting and drying. Good design and careful installation are necessary to prevent damage to foundations caused by the shrinking and swelling." Elsewhere it identifies the soils "likely to swell and shrink enough to damage foundations" as those with a high liquid limit and high plasticity index, or those classified CH (same survey). Published plasticity indices for these series in the adjacent Tarrant County tables run 20 to 36 for Sanger, 20 to 35 for Navo and 28 to 42 for Houston Black, Heiden and Ferris (Soil Survey of Tarrant County).

Development timing matters too. When the survey was written the principal land uses were grazing, crops and urban development, and "urbanization is rapidly increasing in the county" (Soil Survey of Denton County) — most of the county's housing came after that.

For permit requirements, engineer sign-off and watering rules, including any foundation-watering exemptions, see the Denton, Lewisville and Flower Mound pages.