The old school construction material named ‘rammed earth’ is currently undergoing somewhat of resurgence in the construction world, particularly across some of the UK’s more environmentally iconic builds such as the Eden Project in Cornwall, the Rivergreen Centre in Durham, and CAT in Powys.
Traditionally, ‘rammed earth’ buildings are made by compacting or ramming raw earth into moulds or template building blocks. Sand, gravel and clay is added to help stabalise the mixture along with small amounts of moisture to wetten the soil before it is compacted into the moulds.
This technique, thought to be one of the most sustainable construction techniques in existence is more popular on the continent in the UK, but is thought to be utilised more here in the future.
But what are the pros and cons of using rammed earth in modern construction?
- Easily identifiable appearance
- Natural and plentiful resource
- Low carbon emissions associated with manipulating, delivering and building with material
- Material reusable when building is demolished
- Due to high moisture mass, the humidity of the building is well regulated
- Use of local soil supports local economies
- Good at regulating internal temperature of buildings
- Airtight construction is possible
- Issues have arisen about its durability, particularly during extreme weather conditions
- Unable to be fully insulated without additional materials (i.e polystyrene insulation)
- Only certain types of soil can be used in construction of this type
- Construction labour can be expensive due to quality regulations
- Longer construction process
- Not a popular construction technique in the UK, therefore may be unstable in certain UK conditions
- The addition of other construction materials to help stabalise a structure made out of rammed earth
(i.e cement or concrete) can increase carbon emissions therefore ruining environmental benefits.