Sustainable Foundation

Expanded Shale, Clay and Slate (ESCS) Lightweight Aggregate Stands on a 2,000 Year Old Sustainable Foundation

Our Commitment to Sustainable Development

The Expanded Shale, Clay and Slate Institute (ESCSI) and its member companies are committed to providing a product that has both immediate and long-term performance that contributes to sustainable development of the building industry. We realize that to create a vibrant and sustainable society, innovative, practical and responsible designs need to be combined with realistic construction practices. The use of ESCS products in these designs promotes sustainable development and enhances the ability of future generations to meet their own needs.


Structural lightweight aggregate has been used successfully for well over two millennia with some of the Roman structures still in use. The economic benefits that have driven the growth of the ESCS industry for nearly 100 years are the same characteristics that are now being called “sustainable”.

ESCS has been used successfully around the world in more than 50 different applications. The most notable among these are concrete masonry, high-rise buildings, concrete bridges, precast concrete, asphalt chip seal, soil amendment, green roofs, geotechnical fills, and storm water management with on site treatment.

This track record of proven performance demonstrates how ESCS helps designers and owners optimize sustainable development by conserving energy, saving material, labor and transportation costs, improving performance, maximizing structural efficiency, addressing heat-island effects, and increasing service life.

Any additional upfront energy or cost required to manufacture ESCS is paid back during initial construction and/or over the product’s service life. Thinner structural sections lower the overall embodied energy in construction and improved thermal performance produces energy savings for the life of the structure.

ESCS Material

ESCS is produced by expanding and vitrifying select shale, clay, or slate in a rotary kiln. This process creates a high quality ceramic lightweight aggregate that is structurally strong, durable, environmentally inert, non-toxic, highly insulative, and will not degrade over time. Several ESCS Lightweight aggregate producers certify that their ESCS excess fines meet the LEED and ISO criteria for pre-consumer recycled content. ESCS is environmentally friendly product with several benefits that contribute to projects becoming LEED (Leadership in Energy and Environmental Design) certified. ESCS material can contribute to at least 33 of the points available in LEED 2009 for New Construction and Major Renovations.

A Holistic Picture

The sustainability process starts with a decision to create a lifestyle that respects the interdependence of all life. This requires concern for long-term performance with minimal maintenance and energy demand in our designs, as well as efficiency and responsibility in our manufacturing and construction. There are many changes that can be accomplished in the present that will yield positive results for humanity now and in the future. We believe the utilization of ESCS lightweight aggregate with all its positive benefits is an important element in the sustainability of the building industry.

Sustainable Benefits of Using ESCS Over Conventional Normalweight Sand, Stone and Gravel Aggregates

In Concrete and Concrete Masonry

  • Less weight (reduced dead load)
  • Less overall material used (thinner walls and floors use less material themselves and allow smaller foundations, beams and columns)
  • Reduced seismic inertia (more economical design, less materials)
  • Longer spans increasing design flexibility
  • Reduced number of trucks (more building products per load)
  • Easier placement (all products are lighter)
  • Improved workforce sustainability (masons have fewer injuries and safer jobsites)
  • Increased mason productivity
  • Better fire ratings (thinner walls and floors)
  • Improved energy performance with thermal mass, higher thermal inertia and lower thermal bridging
  • Increased durability and service life with improved concrete properties
  • Improved concrete properties through internal curing
  • Improved contact zone between aggregate and cementitious matrix
  • Better elastic compatibility between aggregate and cementitious matrix
  • Fewer overall micro-cracks and macro-cracks
  • Reduced autogenous shrinkage
  • Reduced chloride ion permeability

In Lightweight Asphalt Chip Seal

  • Practically eliminates damage to windshields, headlights and paint
  • Reduces motorist complaints and insurance claims
  • Superior skid resistance, wet or dry, and will not polish as it wears (safer roads)
  • Extends chip seal and roadway service life

In Lightweight Geotechnical Fills

  • Convert unstable soil into usable land
  • Half the weight, higher internal friction angle (reduced dead load & lateral forces)
  • Free draining
  • Provides insulation and is chemically inert

In Horticulture and Green Roofs ESCS is the perfect soil media because it is non-toxic, odorless, 100% inert and will not compress, degrade, decompose, or react with agricultural or horticultural chemicals. ESCS is use as a soil conditioner in plantings, golf course greens, potting soil and as a soil media in both intensive and extensive green roofs. ESCS is also incorporated into engineered structural soil to support healthy plant growth and improve drainage while allowing access by heavy emergency vehicles to the edges of buildings.

ESCS lightweight aggregate:

  • Promotes strong root development
  • Improves aeration and drainage
  • Reduces nutrient loss and improves moisture retention
  • Enhances soil resiliency to climate changes
  • Resist compaction

Storm Water Management and Water Treatment

ESCS can be used to construct vegetated filter strips, rain gardens, rain basins, constructed wetlands and bioswales to treat and reduce the amount of storm water runoff. The voids within ESCS provide an environment suitable for beneficial microbial action that will help to filter storm water. ESCS is also used as the underground-layered aggregate filtering fill beneath permeable pavements. ESCS lightweight aggregate has the following: 

  • Increased surface area with better porosity
  • Larger interstitial space and greater water storage
  • Improved removal of suspended solids, hydrocarbons, metals, nitrogen and phosphorous

In addition, ESCS can be used as part of an on-site sewage treatment system. The void structure within ESCS allows microbes to live, flourish and improve septic systems efficiency. It can also be used in living machines that process a generated waste stream through the use of innovative natural environments that filter and digest wastes in many different stages. ESCS can also be used as filter media in packaged nutrient removal systems and in constructed wetlands.

Regional Material

ESCS is used at numerous manufacturing facilities in close proximity to almost every building site. The 500-mile radius from ESCS aggregate plants encompasses most major markets all across the United States. ESCS products have lower transportation requirements and use fewer trucks to transport the same amount of product when compared to normal weight aggregate or concrete.

By Definition

Sustainability must be looked at with a long-term perspective. A product that is considered “green” today but lowers durability and long-term performance is not sustainable. Conversely, when the energy invested in the production of ESCS is quickly recovered, both in first and ongoing life cycle costs, the material is undoubtedly sustainable. ESCS has been contributing to the sustainability of the site and structure of building projects long before the current green movement came to the forefront. It’s beneficial properties will continue to improve the sustainability of past, current and future projects.