Watershed Materials designs and manufactures a green, low carbon, sustainable building product called the Watershed Block.

Most masonry products used in construction today - including the ubiquitous cinder block - are made by mixing sand and gravel together with Portland cement, a notorious contributor to global CO2 levels. Limestone must be heated to 2700 degrees fahrenheit to make cement, which uses large amounts of fossil fuels. Add to that the energy required to blast and crush virgin rock into gravel and you have a huge carbon footprint.

Watershed Block presents a solution to these environmental problems - a beautiful and versatile masonry unit made of locally-sourced earth and recycled aggregates. Watershed Blocks are manufactured using a proprietary process and activator that actually fuse soil grains and fragments of rock together into a type of sedimentary rock. The result is a rectangular, hollow-celled “industrial stone”, as strong as a concrete block yet with a character, tone, and resonance that expresses local site attributes and adds beauty and depth to architectural designs.

There is an inherent warmth in the color and texture of a Watershed Block, made from natural quartz grains and other minerals.

Rock forms in nature over the course of millions of years as pressure accumulates on top of deposited sediments and fuses the loose grains into solid stone. In geology this process is called lithification - literally “rock growing”. Watershed Materials uses a similar process to make blocks. We start with a precise combination of rock fragments, quartz grains, feldspars, clays, and accessory minerals and then apply intense hydraulic force to mimic the weight of twenty thousand feet of sediment. The result is a dependable structural building block with the appearance of stone and low environmental impact.

We have a goal at Watershed: to make a durable building block from natural materials. Watershed blocks have the visual complexity of sedimentary rock with a shape and design criteria that fit seamlessly into current masonry building typologies - big change, small carbon footprint.

Watershed Block technical details:

  • Dimensions :  4 x 8 x 16”, 6 x 8 x 16”, 8 x 8 x 16” Bondbeam blocks 6” & 8” high
  • Density :  115 to 125 lbs/ft3
  • Weight per block :  Approx. 30 lbs for 8” block
  • Dry compression strength :  Greater than 1900 psi (ASTM C-90 compliant) 
  • 24 hour absorption :  Less than 0.15 by weight (ASTM C-90 compliant)
  • Linear shrinkage :  Less than 0.10%
  • Wet dry durability :  Less than 5% weight loss
  • Thermal conductivity :  0.81 – 0.93 W/m°C
  • Acoustic reduction :  40-50 dB (40 cm wall 500Hz) 
  • Specification :  Alternate Materials
6 inch Watershed Block - produced with locally sourced materials and low cement content.

6 inch Watershed Block - produced with locally sourced materials and low cement content.

Watershed Blocks used in a low carbon, green home

Watershed Blocks used in a low carbon, green home


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