Rammed earth
![]() |
Contents |
[edit] Introduction
The rammed earth construction method is a process of compacting a mixture of soils or aggregates into formwork (or shuttering). The mixture is then compressed (or tamped) manually or mechanically, to form foundations, floors, walls and so on. When made into walls, these rammed earth components are sometimes referred to as pise.
The layers can be rammed continually until the component is complete, with no need to wait for each layer to dry out. The formwork is then removed and a solid, hard building component is produced.
[edit] History
The rammed earth technique is an ancient method of construction, with evidence of its use dating as far back as the Neolithic Period. Early rammed earth structures were made from a mixture of clay-rich soil, water and natural stabilisers (such as animal urine, animal blood, plant fibres and so on).
Rammed earth was used in many parts of the world including South America, India, the Middle East and Africa. This method was not frequently employed in Europe, although some examples survive in France, and it was more popular in parts of Spain. Significant portions of the Alhambra in Grenada (built chiefly between 1238 and 1358) were constructed using this method.
This building method was common in China, where early evidence of rammed earth structures has survived from the second imperial dynasty (202 BC to 220 AD). Several centuries later, large portions of the Great Wall of China (primarily built during the Ming dynasty 1368 to 1644), were also constructed using this method.
[edit] Modern use
Significant monuments and more common architectural structures built using this method have survived into the 21st century, demonstrating its durability. However, the popularity of rammed earth throughout most parts of the world declined with the introduction of modern materials and methods of construction.
In the late 20th century, its popularity surged again amongst architects with an interest in environmental sensitivity and locally sourced - and readily available - materials. These components can include chalk, lime, gravel, sand, silt or clay. Ideally, the soil should be high in sand and low in clay, with modern formulations reinforced by other structures such as beams.
Cement can also be added to the mixture to improve stabilisation characteristics. This formulation, which has become general practice in Australia, is sometimes referred to as stabilised rammed earth (SRE) or cement-stabilised rammed earth (CSRE). It is acknowledged that the addition of cement can reduce the sustainability of this formulation.
Wall thicknesses are usually at least 30 cm, which creates conditions for high thermal capacity and moderate temperature fluctuations. Insulation can be incorporated to improve thermal performance, and protection measures (such as overhangs) can be added to prevent damage caused by water. Surfaces can also be finished with plaster, bitumen or linseed oil.
[edit] Practical considerations
When successfully produced, rammed earth components can exhibit good compressive strength, durability and aesthetic appeal. However, the success of rammed earth construction in a practical sense may be dependent on climate conditions and the availability of suitable materials.
The method typically works best in locations with high humidity and relatively moderate temperatures. In colder climates, rammed earth walls may need additional insulation, while in locations with high rainfall, they will require protection from rain.
In the UK, there has been some interest in rammed earth construction methods. However, the country’s climate has prevented it from becoming widely adopted.
After five years, the corner of the wall at the entrance of the Eden Project already showed surface damage. Although, given the thickness of the walls this probably is not significant and may be partly down to lack of testing and education about this method. |
One high profile example of rammed earth in the UK can be found at the entrance of the Eden Project in Cornwall. Many aspects of the Eden Project championed sustainability, and due to their thermal mass, rammed earth walls fit in with the organisation's environmental ambitions.
[edit] Related articles on Designing Buildings
Featured articles and news
Shading for housing, a design guide
A look back at embedding a new culture of shading.
The Architectural Technology Awards
The AT Awards 2025 are open for entries!
ECA Blueprint for Electrification
The 'mosaic of interconnected challenges' and how to deliver the UK’s Transition to Clean Power.
Grenfell Tower Principal Contractor Award notice
Tower repair and maintenance contractor announced as demolition contractor.
Passivhaus social homes benefit from heat pump service
Sixteen new homes designed and built to achieve Passivhaus constructed in Dumfries & Galloway.
CABE Publishes Results of 2025 Building Control Survey
Concern over lack of understanding of how roles have changed since the introduction of the BSA 2022.
British Architectural Sculpture 1851-1951
A rich heritage of decorative and figurative sculpture. Book review.
A programme to tackle the lack of diversity.
Independent Building Control review panel
Five members of the newly established, Grenfell Tower Inquiry recommended, panel appointed.
Welsh Recharging Electrical Skills Charter progresses
ECA progressing on the ‘asks’ of the Recharging Electrical Skills Charter at the Senedd in Wales.
A brief history from 1890s to 2020s.
CIOB and CORBON combine forces
To elevate professional standards in Nigeria’s construction industry.
Amendment to the GB Energy Bill welcomed by ECA
Move prevents nationally-owned energy company from investing in solar panels produced by modern slavery.
Gregor Harvie argues that AI is state-sanctioned theft of IP.
Experimental AI housing target help for councils
Experimental AI could help councils meet housing targets by digitising records.
BSRIA Occupant Wellbeing survey BOW
Occupant satisfaction and wellbeing tool inc. physical environment, indoor facilities, functionality and accessibility.