FAQs about Rammed Earth

What is rammed earth?

Rammed Earth is an earth based wall system made of compacted gravel, sand, and clay; that is extremely strong and durable.  In modern rammed earth 5-10 % cement is added as specified by an engineer. We add rigid insulation inside the rammed earth wall for thermal resistance as well as steel re-bar for seismic reinforcement. 

Quality rammed earth walls are dense, solid, and stone-like with great environmental benefits and superior low maintenance characteristics.

What about the building code?

A person in allowed to build a rammed earth home or structure anywhere in Canada. There has been no code written yet for rammed earth so what is needed is the stamped approval of an engineer. After that you apply for a building permit and follow the same rules that others do when dealing with the building inspector.

How much does it cost?

The initial cost of rammed earth construction is comparable to conventional masonry construction, however given the longevity of rammed earth the actual cost is considerably less in the long run.   The CMHC estimates the average stick-frame home has a life span of 49 years.  A Rammed earth house can easily sustain its integrity for 1000+ years.    

Primary factors affecting the cost of any project are design and site characteristics.

Is rammed earth safe in earthquakes?

Yes, in an earthquake zone our rammed earth walls are engineered to withstand a major earthquake. We use steel re-bar inside the walls and foundation and small amounts of cement for added stabilization.

What about engineering?

We work with our engineer throughout the process to ensure efficiency. We provide an in house architectural designer to professionally complete working drawings, which are stamped by an engineer. Merging the rammed earth design and engineering process together will save valuable time and money. An understanding of how rammed earth walls are built is very valuable and can’t be underestimated.

Is rammed earth suitable for the cold Canadian climate?

Absolutely, in fact our insulated rammed earth walls have 50% more R-value (R33) than a typical Canadian home (R22). We use four inches of special rigid insulation in the centre of the wall keeping the heat in and the cold out. One of the most important aspects of a rammed earth wall is the thermal mass; a rammed earth wall 2 feet thick can store heat energy between 24 to 48 hours, which can help stabilize the indoor air temperature during winter.

What is the difference between rammed earth and cob?

Rammed earth is a structural wall system, which is composed of gravel, sand, and clay compacted to a stone like hardness. Cob walls are made of sand, clay and straw. Typically cob walls are in-filled between a post and beam structure and when dry, similar to an adobe mud brick. Rammed earth is far superior in strength, durability, speed of construction and seismic considerations.

Is rammed earth suitable for a rainy climate?

Yes, it is a very suitable type of environmental building for a rainy climate such the Pacific Northwest coast of North America where we live. Rammed earth walls do not rot or decompose. Like any building, the most important aspects in protecting your building are the material of the wall system, roof design, strong foundation and good drainage. A well-protected rammed earth building has a much higher resistance to rain than a wood frame home or other structures made of degradable materials. Rammed earth homes routinely last for generations in many types of environments.

What if I already have an architect?

If you have an architect you are committed to we will work together to create a building that is optimized for cost effective construction and suitable to the unique requirements of building with rammed earth.

Can the walls be painted or plastered?

Yes, if you like but it is not necessary.  The walls have an organic beauty in their raw form. Many people choose to leave the walls the colour of the earth used or add pigmentation to the rammed earth mix to give a variety of colours.