History / Technical / Thermal Properties / Benefits / FAQs

Frequently Asked Questions

_3257821What are the Stabilised Rammed Earth (SRE) walls made of?

SRE Walls are constructed utilising a quality road base material (soil and gravel mixture) stabilised with cement.

What colour are they?

The colour of your rammed earth is determined by the soil that is used in the construction of the walls.

Where does the material come from?

The materials are generally sourced form quarries in the area where the dwelling is to be constructed. If suitable soils and quantities are available on site, these materials can be used for the construction of the walls, however generally the material needs to be sourced from local Quarries.

How thick are Rammed Earth walls?

External walls are a minimum of 300mm in thickness which enables them to be load bearing. Internal walls are also generally 300mm but can be reduced in thickness to 200mm however they are not load bearing at this size.

What does a load bearing Rammed Earth wall mean for construction?

Load bearing rammed earth walls can support roof structures as well as second storey floors. This eliminates the need for structural timber or metal posts, and reduces the building time and cost.

Can I ask a dumb question? How do you actually build a wall?

SRE walls are constructed using specially designed formwork. Soil is placed in 150mm layers in the formwork and compacted; this process is repeated until the desired wall height is achieved.

And another… how do they stand up?

The shear mass of rammed earth walls (on average 800kg /m2) make them extremely stable.

Is there a standard wall length and height that should be adhered to for ease of construction or can they be any length?

Rammed Earth walls can be built easily in 300mm increments of height. They can also be constructed with raked or curved tops that vary in height. As the formwork is generally 300mm or 600mm in height, then finishing flat height levels for example at window sills, above windows and doors and roof top plate heights, should always be done in 300mm increment’s.

The length of rammed earth walls is variable and can be longer than the 2400mm sheets as forms can be joined but no longer than 4.5m before an articulation joint is placed.

The restriction’s here can very  as they are due to both the PI (plastic Index) of the material (as the overall wall length is restricted by the lineal shrinkage of the soil).

Being an off form finish, a panel can develop cracks if it is too long. The length and width of any panel must be also be considered, short panels can’t extend as long.

Articulation joints are required to allow for lineal shrinkage, expansion, contraction and movement in the foundations, – they ensure any movement has a point to shift and doesn’t cause cracks.

What happens with plumbing and electrical wiring?

All plumbing and electrical points are positioned internally as the wall is constructed.

How are the walls finished?

The walls are, what is termed ‘off form’, meaning that once the formwork is removed after construction, the natural earth tones are visible and compaction layers produce the unique character of your wall surface. Our walls are treated with a clear acrylic polymer sealer that dust proofs and seals them from water penetration, eliminating the need for rendering or painting the wall surface.

Tell me about maintenance?

As the walls are not rendered, maintenance is minimal. Depending on climate conditions, the sealer applied on external wall surfaces should not need reapplication before 15 years. Internally you should not ever need to recoat your walls.

Can I fix shelves? Hang pictures? How?

Shelving can easily be fixed to rammed earth walls with masonry wall fasteners. Pictures can be hung using a nail, wherever your heart desires, as you do not have to find that elusive wall stud to hammer your nail into.

Are Rammed Earth houses suited to a modern décor?

Yes! SRE walls compliment any décor from rustic to modern design; they are as timeless as the earth itself and will not date.

Why are Rammed Earth homes so energy efficient?

Well-designed passive solar homes coupled with the high thermal mass of the walls, enables them to naturally store energy (warm or cool) creating a stable internal temperature for the dwelling.

How does this compare with other building materials?

Most other modern building materials have a low thermal mass requiring them to use artificial means to stabilise the internal temperature. This in turn consumes energy and costs you in fuel bills.

Energy ratings and Rammed Earth…… I am confused; can you explain how this works?

Having a great solar passive home design is essential, it is not essential to have an energy rating to enable you to build a rammed earth home. Yes, you can have all Rammed Earth Walls!! Please call us to discuss this process.

My property is in a high fire risk area. How does Rammed Earth compare with other materials?

SRE walls are non-combustible and have a high fire rating (4 hours) making them extremely suitable for dwellings in high fire risk areas.

Our block looks difficult. Can you build on it?

Depending on the design of the dwelling most sites are suitable for the construction of SRE walls

We have termites on our property. Why are the Rammed Earth walls termite resistant?

Due to the materials and construction method, SRE walls are deemed ‘termite resistant’ under the Building Code of Australia. When built on a concrete slab, termite protection is required only around pipe work penetrating the slab area, reducing costs associated with termite proofing a dwelling.

Compared with other forms of construction, how does the cost of wall construction compare?

SRE walls are comparable in price with the construction of double brick walls. Due to the energy efficiency of the dwelling, your energy usage is reduced, saving you money every year for the lifetime of your home. They will also outlast many times conventional building materialsmaking them an investment in the future.

Will you design a Rammed Earth home for me that incorporates my ideas and specific needs?

Yes! Contact our sister company: “Eco Sustainable Homes” 

We combine knowledge from a site inspection as well as a brief from you outlining your likes and dislikes, needs and project budget. This enables us to design an affordable passive solar home that meets your needs and blends in with the surroundings and environment.

Do you have any floor plans I can choose from?

As each home is built to suit an individual client’s needs, budget and site, and is unlikely to be suitable to another client, we do not have a ‘set of designs’ for clients to choose from. The advantage of designing and building a new home with us is that it is tailored to your needs and your site, making it unique and special. Go to Eco Sustainable Homes Website to see projects and read testimonials from clients. 

What about the roof?

Roofing materials are not restricted. The roof structure is attached to the SRE walls via a metal tie-down rod embedded 600mm into the wall. The mass of the walls ensures an excellent fixing system.

What happens above windows and doors? Is that rammed earth too?

Generally it is, but design, aesthetics and budget determine whether earth is placed above door and window openings. A minimum height of 300mm above the opening is required.

Will rain damage the walls?

Rain will not damage good quality rammed earth walls. However you do need to ensure that the base of the walls is at least 100mm above finished ground level, and that you do not build up garden beds against the walls.

Do you need verandas?

There is no need to have verandas on your home. If you have the correct eave overhang you will allow winter sun to enter your home whilst blocking the summer sun.

Is the fitting off difficult or more expensive?

No. Generally the same as other building mediums.

Will you build my designer’s / architect’s plans?

Yes, we are happy to work with other designer and architectural plans. We build walls for Registered Builders, Owner builders and Commercial Builders.

Can we see some of the walls or the finished places you’ve built?

Yes, give us a call to discuss this.

We want to build, but don’t know where to start, can you help?

Yes, we provide advice and assistance to our clients from site inspections, design of your home, to any stage of construction through Eco Sustainable Homes , we have also written a blog post about 8 Topics to Research Before you Buy Land if you’re considering building.  

Do I need special permits for stabilised rammed earth?

No, standard council planning and building permits apply. If purchasing land, ensure that there are no caveats attached to the title restricting construction mediums of your dwelling.

How long will it take to build Rammed Earth walls?

It will depend on the design and complexity of the dwelling. Call us to discuss your project, remember that the Rammed Earth Walls Replace, suds, plaster, painting and external cladding – all saving time.

How long will my house last?

You could well be part of an interesting archaeological dig! Rammed earth buildings date back 6,000 years and precede mud brick as a building medium.

I’m sure I have a hundred other questions!

We are more than happy to discuss any you have so give us a call – Contact us.