Brick by brick


The walls of this home were built with Watershed Blocks.


The sustainable and durable Watershed Block.

A new construction material that combines the best of rammed earth with the best of traditional concrete masonry technology has hit the market.

California-based Watershed Materials’ Watershed Block is designed as a sustainable, durable and good-looking material to build homes, schools and office buildings.

Watershed Materials Marketing Manager Alex Wright said concrete masonry (commonly known as the Besser block in Australia) was very durable but not very good looking and with its high carbon footprint, modern builders would be looking to fi nd something more sustainable. On the other hand, he said rammed earth looked good and was generally sustainable but could be costly and time consuming.

“Each rammed earth building must be custom-built on-site, meaning a crew of builders needs to design and build forms then ram the walls, let them set and remove the forms,” Mr Wright said.

“Watershed Blocks uniquely combines the two technologies, improving the sustainability and aesthetics of concrete blocks while making rammed earth more mass produced.

“Watershed Blocks uses locally sourced rock and uses less cement than concrete blocks, resulting in a much lower carbon footprint.”

Watershed Materials Founder and President David Easton established building company Rammed Earth Works 30 years ago, but said there had always been something about the material that bothered him – it was hard to scale.

The Watershed Block was formed out of a desire to create a rammed earth building block that fi tted into the accepted dimensions for concrete blocks.

By reducing the cement needed to produce a durable masonry block, the carbon footprint is dramatically reduced. “The primary ingredient of concrete is cement, and cement has a very high carbon footprint,” Mr Wright said.

“So high, in fact, that six per cent of all the world’s carbon output is from cement production.”

The company has begun trialling on-site block production, which turns excavation materials often found at construction sites into building material.

The project is still in its early days and currently all Watershed Blocks are being made at a factory using quarry materials.

Although several years away, the success of the project would take building sustainability to a whole new level as builders use site waste to construct new buildings.

The pop-up plant also helps to eliminate truck traffi c and reduces the need for imported materials.

Ultra-high compression is applied to loose excavated material and transforms the waste into a sustainable concrete unit.

The process mimics the natural geological process of lithifi cation, turning the mineral grains into a sort of sedimentary rock.

Currently, Watershed Materials is exploring the feasibility of the concept at a large redevelopment project in San Francisco.

CONTACT Watershed Materials