Earth Blocks and Earth Bricks

Earth Blocks

Earth Blocks Ltd are the UK’s only manufacturers and suppliers of cob blocks, cob bricks, premixed cob, earth blocks, earth bricks and shaped earth products. Being the only company in Cornwall manufacturing and supplying earth products is no mean feat, given how much suitable clayey soil is here in abundance. We have been manufacturing cob blocks and cob bricks in Cornwall for the past 2 years and we are continually refreshed by the growing interest shown. 100% sustainable, using 100% natural ingredients, our cob blocks and cob bricks are increasing in popularity for the construction sector.

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cob blocks sustainable building materials

So what is a cob block? What is in a cob block that makes it a cob block? Well, the short answer is straw. We add straw to our clayey soil (and some water) mix it together, mould it and when it’s dry we have a cob block. But what if we didn’t add straw at all? What would the block be classified as? An earth block…..

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…….no straw. Just compressed clayey soil.

Our graded, clayey soil stockpile in the yard is frequently replenished and is currently holding approx 160 tonnes. To make cob (for cob blocks and cob bricks) we use this soil, straw and water and mix it all together with a 7 tonne swing-shovel/excavator. To make earth blocks and earth bricks there is no mixing required…..we scrape what is required from the pile, portion it before it heads off to our block and brick machines.

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Cornish, clayey soil

The 3 sample blocks below display how critical moisture content is during pre-manufacture and the manufacturing process.

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These 3 earth block samples were made on the same day but had different moisture content when compressed.

Earth Block A – too much moisture content within the mixture. We can see that this unit has slumped and is distorted in shape.

Earth Block C – not enough moisture content within the mixture. When this one came out of the machine we could see that the mixture was too dry.

Earth Block B – happy with this one. No distortion or cracking.

Initially, we manufactured just a few 100mm earth blocks as part of our research but wanted to push the envelope and experiment with making larger sized units. This led us to manufacturing 150mm earth blocks…..

Earth Bricks

Having accomplished manufacturing earth blocks, we turned our attention to making earth bricks. These smaller units are a little more forgiving where moisture content is concerned, however, and after a few tests, we got the mixture right……

All of our cob products are dried naturally. They are not fired in any way. Left in the sun and/or drying winds these earth bricks are ready to use after just a few days.