Forms of Earth Wall Construction

by Ciaran Malik

How many forms of earth wall construction do you know?

“Earth construction is fun and once you get started a whole new world opens up. I recently started attending EBUKI training events and was amazed at how many new things there were to learn about earth building. For a start I thought rammed earth, cob and compressed earth bricks were the only ways to build with earth and I now know of at least nine (but I think there could be more).

I have tried to share a brief explanation of them here to get you started. There are some useful things to think about when comparing and choosing one:

• Thickness; these methods vary from a thin plaster coating to walls that 500mm thick, make sure you have space for the system and enough earth to build with.

• Structure; some of these methods are structural (they can support loads/forces) and some are not. The ones that are not, can be used as finishes or internal walls.

• Mix; earth building generally uses sand, clay, fibres, and water. Not all the methods need them all.

• Mixing; I was surprised at how many ways there are to mix earth, from mechanical hoppers to mixing on the ground.

• Building; how they are built up, what tools and temporary equipment might you need.

Mass Earth is a general term for Biggins, Clay, Claywall, Clom, Cob, Dabbins, Mud, Mudwall and Wychert. It is a traditional way to build walls using layers of uncompacted clay, fibres, and other minerals. These walls tend to be thick, 300mm to 500mm range solid earth but are also structural, holding up timber frame roofs. Mixed on the ground and lifted into position, they do not require a lot of specialist tools.

Rammed Earth is when layers of clay, sand and gravel are compacted to make structural walls, with a typical minimum 300mm thickness. This is a drier mix, which is held in place between formwork while it is compacted but then revealed immediately to allow it to dry out.

Moulded and Compressed Earth Block (CEB and MEB) are general term for Adobe, Clay Lump and Mud Brick. It refers to unfired blocks which are either made in a mould and compressed, or made in a mould without being compressed. The bricks and blocks are unfired and made with clay, fibres, and other minerals and can be structural. A 100mm thick wall might be used as a non-structural partition or thermal mass and a 200mm or 300mm thick wall might be used as a structural wall.

Meadow Earth, also called turf wall, is made with blocks cut from the surface soil, keeping the soil, plants, and roots together to build structural walls. The blocks are 300mm to 500mm thick and only need tools to cut and place them.

3D Printed Earth can be similar to light earth or mass earth, but is different because the walls do not have to be solid and less material and voids can be left where it is not needed. It is a mixture of clay, fibre and other minerals which are deposited in layers by a machine.

Earth Mortar is used to hold stone, fired bricks and unfired bricks to make structural walls. The mortar can be made of clay, fibres and sometimes lime is added. The wall thickness depends on the use from 100mm non-structural walls to 200mm or thicker structural walls.

Light Earth is laid or compacted between a frame of columns and beams and made from an equal mix of clay and fibres. The walls are not load bearing walls (they are not supporting vertical roof loads) but by filling the spaces between columns, they contribute to the stability of the building (horizontal loads).

Frame Earth is applied to a timber lattice or weave to make a non-structural wall. It is made from a mixture of clay, fibres, and other minerals and is also called Kebber and Motte, Mud and Stud, and Wattle and Daub.

Earth Plaster is not structural but it creates a wonderful clay finish. A mixture of clay and short fibres are applied to walls, ceilings, and floors. A coating can be 5mm to 30mm and needs similar tools to other plasters.

Having started this bit of research, I think I've started to find some more traditional forms of earth wall construction. This is also a developing area, there is really interesting work into poured earth (without cement), super adobe, cobbauge, extrusion and other forms which are still developing.

Now all I have to do is finish up all those other walls and then do the same thing for earth floors…”

Ciaran got a lot out of 2024’s Clayfest. A summary of this information can be found in our Glossary.

If you have found this useful, get involved with EBUKI and come to some of our events!

You can also find more of Ciaran’s work here.