Whether or not you have heard about rammed earth construction, it’s one of the world's oldest building methods. Rammed earth, a technique dating back to the New Stone Age, has made a revival as a modern and sustainable building alternative.
The process of rammed earth has been around for centuries. Many ancient rammed earth walls, including portions of the Great Wall of China, still stand today as a testament to the durability of this natural and sustainable building method.
Traditional rammed earth involves a mixture of raw materials compacted into engineered form systems, with the correct amount of clay being the binding ingredient. Most modern-day builders are constructing stabilized rammed earth structures, incorporating 6-10% Portland cement into the mix to aid in strength, structural consistency and durability. During compaction, this earth blend is tamped layer by layer, compressed into a strong, dense wall. Modern technology and machinery have only improved the durability and convenience of the technique.
While entire homes can be created from rammed earth, its popularity also extends to furniture, fireplaces and pits, artworks, and more.
What is rammed earth made of?
Rammed earth can be made from a variety of mixtures, but Aussie Built uses a combination of subsoil, sand, gravel, clay, cement stabilizer and a waterproofing additive known as Plasticure by Tech-Dry, developed specifically for rammed earth by the world’s rammed earth leader, Australia. This admixture, Plasticure, is what keeps our rammed earth structures waterproofed throughout, for its lifetime, preventing efflorescence and the need for a damp proof course (although some jurisdictions may still call for a DPC).
To further protect rammed earth structures, topical sealers can be applied after the structure is built. Tech-Dry Earth Binder is the only necessary sealer applied to interior walls to prevent crumbling and dusting of the rammed earth, leaving a breathable, smooth, dust-free wall. Earth binder should also be used to bind the exterior of the rammed earth before applying the waterproof sealer, Tech-Dry Stabilised Earth Water Repellent W. The Stabilised Water Repellent is then applied to the rammed earth wall for repelling any moisture.
Applying sealers as maintenance for optimum wall durability will vary depending on direct weathering. If Plasticure is not used as a waterproofing admixture, maintenance is generally recommended every 3-5 years. Without Tech-Dry’s topical sealers and Plasticure waterproofing the walls, rammed earth buildings are likely to succumb to the elements.
Why build with rammed earth?
There are many reasons to build with rammed earth. Aesthetically, rammed earth is captivating and leaves a lasting impression on all who experience it in person. Each wall is distinct and beautiful, with such depth of touch and sound, transporting you to a different age. When building with rammed earth, you’re building a landmark to be passed down to many generations.
Not only is rammed earth unique in its stunning design, but it is also one of the most environmentally-friendly building techniques in the world. Most of the materials are naturally occurring and remove the need for sheathing, insulation, sheetrock and paint. Forms and tools are reused from job to job, eliminating significant waste.
Essentially man-made sedimentary rock, rammed earth structures are resistant to termites, fires, rot and mold, and tornadoes.
To top all of that off, rammed earth buildings are non-toxic and structurally strong with outstanding thermal mass, minimizing heating and cooling requirements, saving energy and providing healthy air for generations of occupants.
Is rammed earth expensive to build with?
The cost of building with rammed earth varies based on numerous factors, from engineering and design needs to structure size and who is building it. While rammed earth is more expensive and time consuming to build than traditional stick-frame builds, it eliminates the need for general maintenance over time like other traditional building materials that will pay back in years to come.
Rammed earth is ideal for progressive, environmentally-conscious homeowners, architects, and builders that see the value of the product above the dollar sign where building for a lifestyle is preferred over square footage.
How long does rammed earth last?
Portions of the Great Wall of China made with rammed earth remain standing tall an estimated 2,500 years later. Although modern rammed earth structures haven’t faced the same test of time, when built with the appropriate stabilizers and waterproofing, these buildings can last generations.
Want to build with rammed earth?
Connect with the Aussie Built team to learn more about rammed earth.