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FAQ

Frequently Asked Questions

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

We construct SRE walls using a quality road base material (soil and gravel mixture), stabilised with cement. Want to learn more? Check out the blog we wrote!

What colour are they?

The colour of your rammed earth will depend on the colour of the soil and cement used in the wall construction.

Where does the earth for the walls come from?

We generally source the earth from local quarries. If suitable soil and quantities are available onsite; we can use them. However, we typically need to use materials sourced from local quarries.

How thick are Rammed Earth walls?

External walls are at least 300mm in thickness. This enables them to be load bearing.

Internal walls are also generally 300mm thick. Their thickness can be reduced to 200mm, however this means they are no longer load bearing.

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.

Their load bearing abilities eliminate the need for structural timber or metal posts. It also reduces the building time and cost.

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

SRE walls are constructed using specialised formwork.

An earth mixture is hand shovelled in 150mm layers into the formwork and compacted. This process is repeated until we reach the desired wall height.

Want to learn more? Check out the blog we wrote!

And another… how do they stand up?

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

What height and length can the walls be?

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, flat finishing heights should always be in 300mm increments. This could include your window sills, above windows and doors, or roof top plate heights.

The length of rammed earth walls is dependant on the materials and design. Wall sections can be longer than the 2400mm formwork panels as forms can be joined.

The wall length of any one section of rammed earth is restricted by the lineal shrinkage of the soil. This is due to the Plastic Index (PI) of the material.

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

We use articulation joints 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 placed within the walls as they are being built.

How are the walls finished?

The walls are an ‘off form’ finish. This means once we remove the formwork after construction, the wall is ‘finished’. The natural earth tones are visible and compaction layers produce the unique character of your walls.

We also treat our walls with a clear acrylic polymer sealer. This sealer is dust proof, and seals the walls from water penetration. It also eliminates the need for rendering or painting of the wall surface.

Tell me about maintenance?

As the walls are not rendered, and don’t need to be painted, maintenance is minimal.

Climate conditions will determine how often your walls will need sealer reapplied. Typically your external walls should not need reapplication before 15 years. Internal walls should never need to be re-sealed.

Can I fix shelves or hang pictures on Rammed Earth?

Yes! Shelves can be easily fixed to rammed earth walls with masonry fasteners.

You can hang pictures wherever you would like, using an ordinary nail. You won’t need to find that elusive wall stud to hammer into!

Are Rammed Earth houses suited to a modern décor?

Yes! Rammed Earth is a neutral medium that will go with any decor. From rustic to modern; the design and architecture of your home will mean it can suit your personal style.

What makes Rammed Earth homes so energy efficient?

When paired with solar passive principals, the rammed earth walls high thermal mass naturally stores energy. This creates a stable internal temperature of your home, keeping it warm in winter and cool in summer.

How does this compare with other building materials?

Most other modern building materials have low thermal mass. This means they need artificial heating and cooling to stabilise internal temperatures. These homes uses more energy and costs more to live in.

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

An energy rating is not essential to build a rammed earth home. Having a great solar passive design utilising high thermal mass mediums is what helps create a sustainable home.

We would love to discuss this further with you over the phone or in person by appointment, please contact us to find out more!

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

Stabilised Rammed Earth walls are a great medium for high fire risk, BAL 40 and BAL Flame Zone (FZ) properties. Rammed Earth is a non-combustible medium and has a high fire rating (4 hours). This makes it incredibly suitable if you’re looking to build in a high fire risk area.

Our block looks difficult. Can you build on it?

It will depend on the design of your home. However, most sites are suitable for Rammed Earth Wall construction!

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 only required where the slab is being penetrated. Usually this is only around pipe work. This means the cost of termite proofing your home is greatly reduced.

Is Rammed Earth more expensive to build with?

Rammed Earth walls are comparable in price to double brick walls.

However, due to the energy efficiency of rammed earth homes, the ongoing living costs will be greatly reduced. This will mean you save money every year for the lifetime of your home.

Rammed Earth will also outlast many conventional building materials. They are an investment for your home and the environment.

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

Yes, we definitely can! Our sister company Eco Sustainable Homes
will be happy to discuss your project and create a custom designed home incorporating rammed earth.

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

What about the roof?

Having rammed earth walls will not restrict the roofing materials you can use. We attach the roof structure to the rammed earth walls via metal tie-down rods. The rods are embedded 600mm into the walls. The mass of the walls ensure an excellent fixing tie-down system.

What happens above windows and doors?

Generally we build rammed earth above windows and doors. But design, aesthetic and budget can determine whether it is used above openings. A minimum height of 300mm above the opening is required if rammed earth is to be used.

Will rain damage the walls?

Rain will not damage high quality rammed earth walls.

You will need to ensure that the base of the walls remain at least 100mm above finished ground level. This means that you can’t build garden beds up against your rammed earth walls.

Do you need verandas?

There is no need to have verandas on your home to protect your rammed earth walls.

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

Yes! We are happy to work with other designers and architect’s plans. We are happy to 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.

Do I need special permits for stabilised rammed earth?

No, standard council planning and building permits apply.

If you are purchasing land, make sure there are no caveats attached to the title. They may restrict the construction mediums you are able to use for your home.

How long will it take to build Rammed Earth walls?

How long it takes to build your rammed earth walls will depend on the design and complexity of your home. Keep in mind that Rammed Earth walls replace studs, plaster, painting, and external cladding – all saving time.

Please contact us to discuss your project and timelines.

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 pre-date 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.