Rammed Earth Construction Pros & Cons

Rammed earth construction is once again gaining in popularity for home builders looking for eco-friendly options.  With rammed earth, you're using the dirt under your feet (or from a local quarry) to build a house.  This is certainly a "green" practice since it usually makes use of local materials (local dirt!) and you don't need lumber, quarried stone, brick, etc. to be transported from long distances.

Rammed earth construction has its pros and cons of course.  Let's take a look at the positives and negatives.

Pros of Building with Rammed Earth

• A properly sited and designed rammed earth home is ideal for passive solar strategies, so it can be great for an off-the-grid house.  The thick, dense walls absorb the warmth from the sun all day and slowly release the heat into the interior of the house at night.  This helps keep heating bills low in the winter, and these homes tend to stay cool in the summer as well. 
• Dirt is an easy-to-acquire material and while there are some requirements (not all dirt is going to have the right mix of sand and clay), you ought to be able to get it locally, so this tends to be an eco-friendly building material.
• And let's not forget the coolness factor of having a house that is built out of something unique.  In many cases, homeowners wanting to save money help with the building process, and there are even DIY sites out there that will tell you how to make a house on the cheap using rammed earth construction.

Cons of Rammed Earth Construction

• Soil selection needs to be done carefully, and if you are able to use dirt from the building site, you'll end up with some big holes you need to figure out how to work into the landscape.
• Though it might seem that a house made out of dirt would be cheap, rammed earth construction actually tends to cost 5 to 15% more than conventional construction (due to the labor-intensive process of creating the rammed earth forms).
• It's difficult to impossible to create rounded or sculpturally shaped walls the way you can with other materials.  Homes made with rammed earth construction are going to be boxy in nature. 
• In colder climates, you'll probably need extra insulation (it's typical to add foam insulation to exterior walls and then cover it up with stucco).

Source: Living Homes: Sustainable Architecture and Design

Comments

[Pedro Abreu]

My friend, I must tell you that you´re no quite right in some of the cons you´ve posted about rammed earth.
It´s perfectly possible to create rounded or sculpturally shaped walls, and costs tend to equilibrate as the knowledge developments and tecnologies associated to earth constrution grow all over the world.
My best compliments,

[Rick Lindsay - Earth Structures Group]

We would like to add that many hundreds of insulated rammed earth buildings have been constructed by the Earth Structures Group since 1998, both in Australia and the UK, and most recently in Sth Korea. These walls use a 50 to 100mm Styrofoam panel in the centre of each wall, combined with patented stainless steel pins that bridge the two walls together. These walls achieve an R rating of 2.7 up to 5.2, depending on the width of the Styrofoam used. The beauty is you gain a high R rating while maintaining a useul U value to store and release passive heat and "coolth". Also the insulation is hidden from both sides with a minimum 175mm cover of beautiful rammed earth. Check our website www.earthstructures.com.au for more information.

[devin]

well i think that these are very nice homes
but i really want to see something more interesting
not that these arent very interesting