Rammed Earth Construction
Aussie Built makes Stabilized Rammed Earth structures with modern form systems, additives, and specific engineering. Mixing subsoil, sand, gravel, and clay with a cement stabilizer and an Australian waterproof additive to create homes that will last a lifetime. The Earth mixture is tested to meet engineered specs and customers desired appearance.
Rammed earth structures are unique in their beauty, longevity, sustainability and comfort of living. The sheer presence of a rammed earth structure leaves a lasting impression on all who experience it in person. It is not only beautiful in design, rammed earth is one of the most environmentally-friendly building processes in the world.
It makes sense
Despite being unique and beautiful. Rammed earth structures are free of toxins, termites and are of the highest fire rating. With 18” thermal mass walls that allow the inside temperature to remain more constant and maintenance free load bearing walls that can support a concrete ceiling if needed for tornado protection, these structures are built to last.
Environmental & Health
Above all, rammed earth walls are supremely environmentally friendly, more so than any other type of solid masonry product. Subsoil often found on site or nearby can be used and amended with quarry soils if needed. All forms are reused from job to job. Savings of dimensional framing lumber, sheathing, insulation, sheetrock and paint allow for a complete stabilized rammed earth wall system. This creates safer, beautiful, environmentally friendly buildings.
Because of the outstanding thermal performance of rammed earth buildings, heating and cooling requirements are minimized and substantial energy savings can be enjoyed over the life of the building by generations of occupants.
Rammed earth walls look as if they have "grown out of the ground" blending harmoniously with their surroundings, especially when materials are used from the construction site. The natural earth walls are unique and completely non-toxic.
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Rammed earth has been used for centuries to build walls and structures all over the world. Many ancient rammed earth walls are still standing today as a testament to the durability of this natural and sustainable building method. The roots of rammed earth date back to Neolithic sites of China. The oldest portions of the Great Wall of China were built using this technique.
Australia, Europe, The Americas, and multiple cultures latched onto rammed earth architectural techniques. Popularized in the United States by S.W.Johnson’s Rural Economy published in 1800, the method was used to construct the US National Historic Landmark, Borough House Plantation, the largest rammed earth building in the US
Standing the test of time, rammed earth has re-emerged as a method of choice for environmentally conscious homeowners, architects, and builders all over the world. Australia being the forefront leader in Rammed Earth developments.
Soil evaluation & Stabilizer
A variety of tests are conducted to determine the suitability of the local soil for construction material. For example, a particle determination test reveals the relative proportions of rock, sand and fines in the sample. A small test wall is built to determine color and strength. Further testing is performed at a geotechnical laboratory.
If the native soil is unsuitable or inadequate for building, it can be blended with or replaced by soil from another source. Soil may be purchased from a quarry, or it might be available as refuse from a nearby site.
Footings & Stem Wall
Concrete footings and stem walls are built to meet Engineered approval. The stem walls are a minimum of 6” above grade with footing drains where needed.
Setting Wall Forms
3/4” HDO ply forms with strongbacks and walers are used for the main form set. Volume Displacement Boxes for windows, recesses and doors can be built into the walls or sectional walls built to accommodate openings. The forms are removed and reset to form the next section of wall. Framing is a major component of the construction process, in terms of both importance and time; it usually takes less time to fill and compact the soil within the forms than it does to set, align, VDB’s, trim and relocate the formwork.
Tamping The Soil
Traditionally, a 5-7 in layer of moistened soil is placed inside the form with the crucial amount of clay colloids as the binding agent, and a worker drops the tamper from a height of 12-18 in. Now days the ramming is done quickly with pneumatic tampers and cement as a stabilizer allows us more structural strength and soil choices. Manual devices are used only in tight spaces around electrical boxes or plumbing pipes or if the need for less noise is essential.
Full compaction of the mix is determined through experience and by the change in tone of the tamper. The layer or lift compacts to 2/3 of its original volume. Another lift of prepared soil is added, and the ramming process is repeated until the desired height is achieved.
After the forms are filled to the desired height with fully compacted soil, a concrete bond beam attached to the footing with rebar is poured on top of the walls to tie the wall system together and to allow for a good fixing for the roof or frame.
Finishing The Walls
It is highly recommended to leave the rammed earth walls in their natural beauty. We use and are distributors for Australian Tech-Dry products specially designed for rammed earth. Plasticure; a breathable waterproof admixture when added to the soil mix will waterproof the walls throughout.
Without Plasticure an exterior clear breathable Waterproof Sealer should be applied to the walls. A separate breathable Earth Binder is used for interior faces of walls to prevent dusting. Walls can be plastered, sandblasted for texture, stained or painted for the desired look.
But nothing compares to the layered sedimentary look.