Calcined Clay vs Expanded Shale-What’s the Difference

Both Calcined Clay and Expanded Shale topdressing products are made from natural occurring earthen materials that are found in specific locations in the United States. After these materials are mined, they are both processed and heated at very high temperatures to stabilize their physical structures. This protects the physical integrity of the individual particles against the wear and breakdown that can occur from the abrasive actions performed while maintaining the surface of a skinned infield. The heating process also affects the absorption rates of water into these products.

These materials should only be used on the surface of your infield skinned areas where they supply the biggest benefits for the best value. Incorporating or tilling these into your infield soils drastically decreases their value and contributions to the overall performance of the infield skin. A topdressing layer of 1/4″ to 3/8″ on the surface of your infield helps in managing your infield’s moisture, creating the perfect sliding surface and really makes maintaining your infield much easier.

You can use these materials individually as a topdressing or blend them together at the ratio you believe provides for the best performance on your infield surface.

Calcined Clay Conditioners

DuraEdge Pro Slide Engineered Calcined Clay Conditioners

  • Raw material: Montmorillonite Clay
  • Heated to 1300° F
  • High moisture absorbing capacity
  • Best for absorbing excess water on infield after a rain
  • Releases moisture slowly back into the soil
  • Used as topdressings and drying agent (available from Beacon in 4 different gradations)

Expanded Shale Topdressing

DuraEdge ProSlide Engineered Expanded Shale Topdressings

  • Raw material: Shale
  • Heated to 2200°F
  • Low moisture absorbing capacity
  • Allows moisture to drain through topdressing layer to infield soil below where needed
  • Faster drying topdressing particles since they cannot hold much water on their own
  • Use only as topdressing (available in brown or red)

View Soil Top Dressings

Paul Zwaska (contributor)

A former head groundskeeper for the Baltimore Orioles, Paul has been a frequent contributor to Beacon’s Ballfield Blog and other resources and products. Among other contributions to Beacon, he authored Groundskeeper University, the pioneering online ballfield maintenance training venue.