How does Garber Sandstone affect Oklahoma foundations near OKC?

Reviewed by Preston, Oklahoma foundation repair consultant · Updated 2026-10-14

In short: The Garber Sandstone is a Permian sandstone with shale and siltstone layers that reaches the surface on the east side of Oklahoma County. It weathers into loamy, well-drained soils that are often shallow to soft rock. These soils generally swell less than the red clays to the west, so drainage, erosion and shallow rock are the usual foundation questions.

What is the Garber Sandstone?

The Garber Sandstone is an early Permian rock unit, deposited in a delta setting, made of lens-shaped beds of sandstone, shale and siltstone ². A regional groundwater study for central Oklahoma describes it as fluvial channel deposits with scour-and-fill sandstones, and the upper Garber in the west as wide, uniform sand sheets ¹. A lens is a layer that thins out sideways, so a sandstone bed under one house may be shale under the next.

Where it is at the surface

The rock layers in central Oklahoma dip west at roughly 35 to 80 feet per mile, depending on location ¹. As a result, the Garber is at the surface on the east side of Oklahoma County, while on the west side of the county a well can pass through up to 1,000 feet of Hennessey shale before reaching it ¹. Edmond sits on the northern side of the aquifer, where the sandstones are better sorted ¹. See the Hennessey Shale page for the clay ground to the west.

Part of the main aquifer

The Garber Sandstone and Wellington Formation form the primary flow system of the Central Oklahoma aquifer, which is why it is often called the Garber-Wellington aquifer ². The aquifer covers about 2,000 square miles ¹.

What soils form on Garber sandstone?

Series	Depth to soft rock	Drainage	Slopes
Darnell	10–20 in ³	Well to somewhat excessively drained ³	1–45% ³
Lucien	10–20 in (14 in typical) ⁶	Well drained ⁶	1–30% ⁶
Stephenville	20–40 in ⁴	Well drained ⁴	1–25% ⁴
Zaneis	About 40–60 in ⁵	Well drained ⁵	0–8% ⁵

Darnell formed in Permian sandstone on ridge crests and upper hill slopes ³.
Stephenville formed in material weathered from Permian sandstone on hill backslopes ⁴.
Zaneis formed in residuum from interbedded Permian sandstone and shale on low hills, and its subsoil is fine-loamy ⁵.
Lucien formed in sandstone interbedded with clay, siltstone or sandy shale ⁶.

Soil surveys record the top of this soft, weathered sandstone as a paralithic contact, meaning the soil rests on rock that is weak rather than hard ³⁴⁶.

What does Garber sandstone mean for foundations?

Lower swell, but not zero

The Garber soils above are classed as loamy or fine-loamy, not clayey ³⁴⁵⁶. However, the Garber itself contains shale and siltstone lenses ², and Zaneis and Lucien formed partly from shale or clay layers ⁵⁶. A lot can therefore have a clayey pocket that moves seasonally even in a sandy area. See shrink-swell and the active zone.

Shallow soft rock

Where soft sandstone is within 10 to 40 inches ³⁴⁶, footings may bear partly on rock and partly on soil. Different support under different parts of a house can show up as differential movement at additions or cracks where one support type meets another.

Erosion and runoff

Darnell has very high permeability and medium to rapid runoff, and Lucien has very high runoff ³⁶. On sloping lots, concentrated roof water and leaks can wash out soil beside footings. See erosion, undermining and washout voids and surface drainage and grading.

Common questions

Where is the Garber Sandstone at the surface?

It crops out on the east side of Oklahoma County. The rock layers dip west, so on the west side of the county the Garber lies under hundreds of feet of Hennessey shale.

Do Garber Sandstone soils swell like red clay?

Soils formed on Garber sandstone, such as Darnell, Lucien, Stephenville and Zaneis, are loamy and well drained. They generally move less than the clay soils on Hennessey shale, but clay and shale layers within the sandstone can still produce clayey spots.

Is the Garber the same as the Garber-Wellington aquifer?

The Garber Sandstone and the Wellington Formation together make up the main water-bearing part of the Central Oklahoma aquifer, often called the Garber-Wellington aquifer.

How deep is rock on Garber soils?

It varies by series. Darnell and Lucien reach soft sandstone at about 10 to 20 inches, Stephenville at 20 to 40 inches, and Zaneis at about 40 to 60 inches.

Sources

OK County Groundwater Model (Project 174601) Association of Central Oklahoma Governments
Review of the general geology and solid-phase geochemical studies in the vicinity of the Central Oklahoma aquifer (Circular 1019) U.S. Geological Survey
Official Soil Series Description: DARNELL Series USDA Natural Resources Conservation Service
Official Soil Series Description: STEPHENVILLE Series USDA Natural Resources Conservation Service
Official Soil Series Description: ZANEIS Series USDA Natural Resources Conservation Service
Official Soil Series Description: LUCIEN Series USDA Natural Resources Conservation Service

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