Rammed Earth Construction - Ghana

(14 Jan 2019) LEADIN:
Rammed earth is a construction method that has been around for millennia, but it's attracting renewed interest in countries like the USA and Australia.
In Ghana a construction company is returning to the technique of rammed earth building, promoting its eco-friendly and economical technique.
STORYLINE:
This construction worker is part of a team building an eco-friendly house near Ghana's capital city, Accra.
He is compressing a mixture of raw materials mostly sourced from within two kilometres.
When the temporary structure is later removed it will reveal a solid wall – the beginning of a house.
The technique is called rammed earth, as co-founder of Hive Earth Kwame de Heer explains.
"Rammed earth is a really old technique. Here in Ghana we have always built houses using mud, but here we have modernised it. We use a mixture of laterite which contains sand, a bit of silt, clay and some stones. We pour this into a temporary structure after being mixed. After pouring in eight inches we compress it to about four inches. We are mimicking a sedimentary rock, but speeding up the process. It's man-made stone."
About five percent of the raw materials used in this method requires imported cement, which is necessary as a stabiliser.
As well as being more eco-friendly, Hive Earth says it costs a third less than building with sandcrete blocks, commonly used in Ghana.
Foster Osae-Akonnor heads up Ghana's Green Building Council:
"Once you can get materials from the locality that you are working, then it helps to reduce the carbon footprint. In addition, comparing rammed earth to concrete, you save all the embodied energy that will be required in the manufacturing of cement."
Compared to other building materials, a very high amount of energy is consumed to produce cement. In addition cement is imported into Ghana.
Another of Hive Earth's rammed earth projects, in Accra, reveals its interesting aesthetic, which is the result of the ramming process.
The technique is well suited to the hot climate of Ghana as it keeps the room temperature cool, says co-owner of Hive Earth, British-Ghanaian entrepreneur Joelle Eyeson.
"Rammed earth is sound proof, it's termite proof, it's thermally insulative – so it regulates the internal room temperature. Because the walls are so thick it takes a while for the heat to penetrate through to the internal room. Our walls can be anything from 12 to 15 inches thick. It's earthquake resistant as well, due to the monolithic nature of the walls as compared to sandcrete blocks, because the walls are monolithic. With sandcrete blocks you have the mortar joints so it's easier for the wall to shake and become disinbursed, whereas with rammed earth it's just one straight monolithic wall. It's as strong as concrete as well – it can last for hundreds of years."
A long-standing example of rammed earth is the Great Wall of China.
Williams Nimailo from the Ghana Bureau of Standards helped draw up the country's new building code.
Allowance is made for rammed earth under both traditional and green building construction methods. Provision is made for modern materials such as clay-fired bricks or cement blocks.
Akosua Obeng is an architect who contracted Hive Earth to build the external walls of a luxury complex in Accra.
Obeng believes using rammed earth techniques in a high-end development will help to change perceptions about how earth materials can enhance design and architecture.
Hive Earth have produced eight rammed earth projects since starting up in 2016, and have many more projects planned in Ghana and regionally.

Find out more about AP Archive: http://www.aparchive.com/HowWeWork
Twitter: https://twitter.com/AP_Archive
Facebook: https://www.facebook.com/APArchives ​​
Instagram: https://www.instagram.com/APNews/


You can license this story through AP Archive: http://www.aparchive.com/metad....ata/youtube/8e7479c9