Gravel, Stone and Sand near Somerset, PA, 15510

Drainage starts with the native soil

At the ZIP's mapped location, the USDA soil survey rates the Rayne-Gilpin channery silt loams as well drained and places them in hydrologic group B with moderate infiltration. Because this soil moves water at a moderate rate, use a compacted angular-stone base beneath a driveway or patio to manage water instead of relying on fines alone.^[1]

The same USDA mapping shows 3 to 8 percent slopes, with Rayne making up 60 percent of the map unit. On these slopes, grade the finished stone surface and base to direct runoff away from the work area.^[1]

Rain and freezing call for a stable base

The NOAA station at Hidden Valley, PA, about 10 miles away, reports 55.9 inches of average yearly precipitation. Place Drain Rock where a driveway edge, patio edge, or low spot needs a freely draining stone layer.^[2]

At the ZIP's mapped location, ground elevation is 2,180 feet, and the Hidden Valley station records 142 days each year when the low reaches 32 F or colder. For a driveway or patio base exposed to these freeze cycles, use crushed angular stone compacted in a stable layer before placing the surface material.^[2],[3]

The NOAA station gives May 2 as the median last spring freeze and October 17 as the median first fall freeze. For garden beds, apply Shredded Mulch after planting around the freeze dates to cover the soil surface and limit splash from seasonal rain.^[2]

Bedrock depth affects deeper excavation

The USDA soil survey describes the top mineral layer as channery silt loam and places lithic bedrock at about 55 inches. For a garden bed or a project needing deeper soil, build the growing layer upward with Top Soil because depth below grade is limited.^[1]

The mapped bedrock is within the Glenshaw Formation, which includes shale, coal, sandstone, clastic material, and limestone. When excavation reaches the lithic bedrock reported at about 55 inches, use a stone base where the planned project needs firm separation above that restrictive layer.^[1],[4]

Choose the base for the project load

The USDA survey reports low shrink-swell, with linear extensibility of 1.5 percent in the top 100 cm. This supports a well-compacted Crusher Run or Road Base layer for a driveway or patio base, with material selected for the load above it.^[1]

Pennsylvania DOT names Subbase, No. 2A aggregate, Section 350, Publication 408 Specifications (2026 Edition, Change No. 1) as a road-building standard. For work governed by that standard, use the project requirements to determine the required aggregate details.^[5]