Introducing Aubrick

A carbon negative earth brick, supplied in partnership with earth4Earth

Over the past four years we have explored one of the world's oldest building materials: bricks. Traditionally in the UK we use fired bricks, made from quarried clay, and fired in gas-powered kilns at high temperatures. This carbon-intensive process is a classic example of linear manufacturing, where a company extracts material, processes it, creates waste, and makes a product with no plan for its end of life. This is sometimes referred to as "take, make, dispose".

As with our work developing Foresso, we looked at this as a challenge of how to create a circular economy where one did not exist. We explored different ways of processing post-industrial waste from the brick industry, from low-value aggregates to bespoke handmade terrazzo.

Unfortunately, the inputs and outputs of the fired brick manufacturing process did not suit our manufacturing capabilities at the time, and we were not able to take a product to market, despite numerous interesting experiments.

earth4Earth, our technology and manufacturing partner, came at the problem from the other direction. Rather than finding a use for fired brick waste, they make a brick that never needs firing. Inspired by rammed earth buildings, they bind waste soil from construction sites with lime and compress it into a brick using hundreds of tonnes of pressure. Avoiding the quarry, the kiln, and the waste.

Conventional lime carries a double carbon cost: the fuel that heats the kiln, and the limestone itself, which gives up its own carbon dioxide as it burns. earth4Earth makes theirs at room temperature from raw materials that are naturally free of carbon, so neither release happens. Once the brick has been made, the lime starts to take carbon dioxide out of the air, turning it into calcium carbonate within the body of the brick. It absorbs up to 178g of CO₂ per brick, or 35g per slip, and what it takes in it stores permanently. Aubrick's life cycle carbon is set out in a published Environmental Product Declaration (EPD).

Compressed earth has a long track record. The rammed earth 'tulou' buildings in Fujian, China, have stood through centuries of subtropical monsoon. Aubrick is tested to the same standards as fired brick. It is UKCA and CE marked, non-combustible, rated for the most severe frost exposure the standard recognises (F2), and it's installed the same way as any brick or brick slip.

Conor Taylor, Creative Director at LCI, says: "Our new partnership with earth4Earth is an amazing opportunity for us to make an impact on the carbon footprint of the built environment, while continuing our design ethos of warm, welcoming, and practical materials. Aubrick is a modern version of one of the oldest building materials and it has that combination of manufactured and natural that makes a material really special. We can't wait to see what architects and designers do with it."

The range launches in two colourways. London Yellow is a warm, sandy buff, close in tone to London stock brick. Welsh Grey is a cool mid grey, with faint, lighter clouding across the face. Both come as 22mm slips in two finishes: smooth, which is fine-grained and lightly pitted, and rustic, which opens the face to show the aggregates running through the body of the material. Full bricks are available in the smooth finish. Custom colours and formats can be made on a project-by-project basis.

The two formats suit different jobs. Full bricks build walls like any other brick, and laid on edge they work as paving, as at a project in Tongxiang. Slips can be installed as cladding using traditional methods or a rail system, and as flooring they can be laid in patterns such as herringbone or basket weave.

Aubrick is already in use at scale. At United Water's plant in Tongxiang, China, 200,000 bricks make up wall panels, herringbone paving, and a boundary wall, able to absorb up to 35.6 tonnes of CO₂ and made from more than 400 tonnes of excavated soil and sand. In Manchester, a 4 x 4 metre wall at Sustainable Ventures is built from 1,200 bricks.