Basic info
Rammed earth is a precisely controlled mixture of gravel, clay, sand, cement and sometimes lime or chemical admixtures which is carefully proportioned, mixed to the correct moisture content, and then machine-compacted in removable formwork to yield a dense, hard, stone-like wall.
Our successfully completed projects throughout Australia include houses, home units, wineries, chalets, hotels and motels, tourist resorts, studios, taverns, schools, and a cathedral. As well as being structural and predominant walls for almost any building, Ramtec walls can also be used as retaining walls, boundary fences, floors, fireplaces, and feature walls.
Thermal and acoustic advantages
Besides their striking beauty and characteristic deep reveals, rammed earth walls have outstanding thermal and acoustic benefits. They have an ideal thermal transmittance (U-factor) and density or thermal storage (known as the “thermal flywheel” effect). This unique combination of properties creates a high thermal mass building, which evens out day/night temperature fluctuations and forms a comfortable building in which to live all year round.
No, quite the opposite. Ramtec walls have good sound-absorbing characteristics and can be built to have very high sound attenuiation (up to STC 57) which inhibits noise transfer between rooms extremely effectively. Common sound reverberation levels are simply not present in our buildings and visitors usually remark on the tranquil ambience of our Clients homes.
Although walls can be from 200mm to over 1000mm, the optimum thickness is 300mm (12″) thick.
Earthquake and cyclone performance
Rammed earth walls are built as articulated free-standing masonry panels. This method of construction is preferred in seismic areas and/or problem sites where ground movement occurs due to subsidence, subsoil movement, or from clay heave and shrinkage. Where the panels are articulated, movements of the ground are naturally better accommodated than in conventional brick buildings.
Excellent. We design further precautions into the structure, to hold down the roof by having steel “hold-down rods” from the concrete foundation through the wall to the roof. Rammed earth buildings have now been successfully built in most cyclone areas of Australia. The Directors of Ramtec built the first modern rammed earth house in Australia in Darwin in 1976 following Cyclone Tracey and it still meets all subsequent cyclone codes to this day!
Construction
Because of our advances, we have dramatically brought down the cost of our walls to compete with the 3 meter high double-brick/plaster/paint combinations.
When the thermal properties of Ramtec walls are considered, together with their superior low maintenance qualities, then the costings show that Ramtec walls are cheaper than any other method of providing similar thermal mass and acoustic attenuation. Naturally, factors affecting costs also include such things as size and complexity of project, locality and site considerations, raw material costs and availability, but generally all our clients are delighted with the outcome.
Yes, especially on larger land holdings with greater areas for selection.
Is rammed earth cheaper than conventional materials in country and remote areas?
Generally yes, since rammed earth materials can usually be found on site in open country areas. If accommodation for our workmen is cheaply available near the site, if the design suits the Ramtec system, then rammed earth is often less than the double brick alternative.
This requires expertise and detailed laboratory measurements. While an experienced visual assessment of a soil being suitable can sometimes be given, there is no substitute for a detailed technical evaluation. RED provides a full range of soil testing services.
Construction
Yes, the configuration is different. However, a similar or lesser amount of concrete is generally required so that overall the foundation and slab costs for a rammed earth house are similar to a typical brick house.
Yes. Whilst these are complex to construct successfully, they are nevertheless cost competitive. Using rammed earth for the foundations, floors and walls totally eliminates the need to get concrete to site and hence, one trade.
Yes. Brick, stone, layered rammed earth and other special effects are all possible and the outstanding appearance generally outweighs the increased cost.
Yes. Wooden floors can be built at ground level or at every other level desired.
Yes. These harmonise wonderfully with surrounding rammed earth walls in the house and garden. These floors can be used inside the home and also outside for verandah and patio areas. Thicker rammed earth floors internally (using Ramtec blends) also allow economical realisation of some powerful passive solar aspects.
Rammed earth. When rammed earth is used for internal walls, the house gives a much better overall thermal and acoustic performance. Internal mass of all buildings is an important aspect of comfort. While internal walls can be constructed of other materials the use of rammed earth both inside and out has structural, aesthetic, and thermal advantages.
In Australia the highest single rammed earth wall is 9 metres high, while a four-storey resort/hotel is the overall tallest modern rammed earth building. About 10 stories would be the highest that rammed earth walls could be built in a modern setting. Double and triple storey houses are built with 300mm thick, load bearing rammed earth walls.
Yes. Rammed earth walls can be designed to adequately take the weight of an upper level of masonry or lightweight framing.
Yes. Any floor can be concrete, timber, or steel framed.
These are built in at the construction stage. Conduits are built into the wall for electrical wiring to be run after the walls are completed. Plumbing can be built into the walls directly, or provided for in embedded conduit, or chased into wall areas that will be tiled over later, such as shower recesses, et cetera.
No. A simple render coat is first applied to the wall to even out any irregularities, followed by the standard tile adhesives.
Well-designed rammed earth buildings with good access and services, etc. will always go up faster than double brick and plaster.
No. This also improves site security and eliminates the typical building site damage to these items. Furthermore, this allows our Clients to budget their cash flows more smoothly without having to lay out for all the major purchases at the beginning.
Styles and designs can vary dramatically, and will be to your own taste. The materials used however are normally from three categories.
Timber framed windows are considered aesthetically appropriate, but should have substantial sections to balance against the “size” of the rammed earth walls.
In most cases, our clients prefer aluminium because it is very low maintenance, glass can be easily replaced in cases of breakage, there are new colours coming out every year, and it’s termite proof. Steel can be used, and can be quite artistic, although generally it is substantially more expensive.
Yes. Aluminium, like timber and steel windows can easily be fitted into our walls, and in all cases they are positioned and fixed after completion of the walls.
Yes, lintels above windows and doors are relatively difficult to construct compared to regular ground level walls. Aesthetically however, rammed earth lintels are desirable and there are several methods of constructing them cost effectively to achieve the outstanding appearance they can give to a project.
Ramtec walls generally require no maintenance. Unlike brick or stone, there will never be any re-pointing or mortar repairs needed, and if our walls are exposed to fierce or extreme weather conditions, we not only formulate our walls accordingly, but any additional surface coatings thought necessary can be easily applied afterwards.
Yes. The cost of having plans drawn up by an architect experienced in rammed earth is the same as any other architect. However, cost savings for clients are guaranteed if the architect is well versed in the methods of construction, the formwork, access, and sequencing parameters of Ramtec.
Yes. Rammed earth retaining walls are economically viable but like all walls, they also need specific designing and damp treatment. We structurally engineer and certify as required.
Colour and texture
Most natural earth colours are available, from the warm reds of central Australia, through the yellow and brown spectrum of gravel ridges, to the creamy finishes with coastal limestone materials. Sophisticated artificial colours and textures are also available, though more expensive.
No. Coarse, medium and smooth finishes are available both with and without pebbles. The ingredients used, together with the placing and ramming techniques employed, determine the colour and texture of the walls. These can be tailored to suit most colour and textural preferences.
Under normal circumstances, no. A clear surface coating applied to a pebbly finish or a smooth finish prevents dusting or pebble dislodgement.
Yes, but generally none are necessary. Unlike standard walls, chipping or scratching Ramtec walls does not expose a different material or colour behind the surface. Nor do our walls ever need painting!
If desired, our walls can be tiled, rendered, bagged, plastered, painted, or virtually any other finish that can be applied to brick or concrete can be applied. Additionally, lime washes, earth renders and other soft earthier finishes can be applied to our walls.
Strength and durability
Ours do not! That is the reason we only use Ramtec walls. Ours will not even disintegrate any faster than other masonry systems with time. While Ramtec walls are inherently waterproof to a substantial degree, integral admixtures can be used and/or clear surface coatings can be applied to walls if needed for even higher performance.
Verandahs represent good usable living space in the Australian climate at reasonable cost. While they do protect walls and are considered desirable, they are not absolutely necessary. Architectural styles do not always include verandahs but these too have been constructed successfully by us.
Fire tests to AS1530.4 (1985) on a 300mm thick rammed earth wall with 6% cement gave 240/240/240 for structural adequacy/integrity/insulative capacity. Ramtec walls can be built to have a four-hour fire rating which is the highest needed in Australian general building codes. Furthermore, our Ramtec walls do not burn or evolve smoke or toxic chemicals, as do some other building products.
Building Codes call for a characteristic compressive strength of not less than 2 MPa which Ramtec walls exceed. Standard 300mm Ramtec walls can be built as load bearing constructions for up to four stories high, but can be designed to go up to ten stories if required.
No. Physical conditions such as cavities or timber framing do not exist within our walls. The CSIRO has even published technical reports stating that termites will not burrow in rammed earth walls. We have also developed a range of techniques to prevent termites from entering a building.
Thousands of rammed earth buildings constructed centuries ago are still giving excellent service in France, Algeria, Morocco, Central America, China, and the Middle East.
In Australia there are many rammed earth buildings over 100 years old still in use. One of the oldest buildings in Western Australia is in Albany at Strawberry Hill Farm where the rammed earth building (built of local materials, with no cement and no verandahs) is over 160 years old and still giving good service. We can only imagine how long our Ramtec walls will last!
Environmental attributes
Rammed earth is probably the single lowest environmental impact building system that is readily and commercially available today for solid masonry buildings.
Rammed earth walls are structural immediately upon completion of compaction and removal of formwork. There is no firing process as used in brick manufacture so there are no kilns, toxic emissions or damaging greenhouse gases. Kiln gas pollutants associated with brickworks are simply not present in the manufacture of rammed earth walls and therefore not emitted into the atmosphere.
Because of the outstanding thermal performance of rammed earth buildings, heating and cooling requirements are minimised and substantial energy savings can be enjoyed over the life of the building by generations of occupants.
Rammed earth walls look as if they’ve “grown out of the ground”, especially where materials have been taken from the site to construct the building. Rammed earth buildings are supremely environmentally friendly, blending harmoniously with their surroundings. The natural walls are sun dried and completely non-toxic.
Bank loans, shire approvals and insurance
Yes. Most major banks and building societies have financed Ramtec walls for housing and commercial projects. Generally, their most favourable terms apply.
No. Ramtec was instrumental in having rammed earth written in to the Building By-laws of Western Australia and then in to the Building Code of Australia.
Rammed earth has been approved for use in every shire in Australia. An Australian Standard on Rammed Earth and other forms of Earth Building is under preparation and RED’s Managing Director is a continuing member of that Code Committee (BD83).
No. Most major insurance companies have insured buildings with Ramtec walls and usually their lowest ratings apply.
Very good. Real estate agents have commented that rammed earth buildings are much easier to sell than conventional buildings. Certainly in some areas, it has even been proven that rammed earth is a definite plus when selling a house or commercial project.
Do-it-yourself
Like all aspects of building construction, the answer is yes.
However, specialist knowledge and equipment is essential and you would be wise to pay for this. Modern rammed earth construction is sophisticated and it is not easy to achieve the high specification, longevity, and quality finish of a Ramtec wall.