Rammed earth is a timeless building technique that combines natural beauty with strength and thermal mass. Made by compacting a mix of gravel, sand, silt, clay, and a stabilising agent—typically cement—into formwork, rammed earth creates solid, durable walls with a distinctive, earthy aesthetic.
At Rammed Designs, we specialise in stabilised rammed earth construction, combining traditional knowledge with laboratory testing and the project engineer's design to deliver walls that are visually striking. Rammed earth's thermal mass absorbs and releases heat slowly, which can moderate daily temperature swings when the building is designed to use it. Results depend on design, orientation, shading and climate.
Made from natural mineral materials, with high thermal mass and a long service life when properly designed and maintained, rammed earth suits a wide range of homes and buildings. Every wall we build is unique, reflecting the tones and textures of the local landscape.
Key Benefits:
- Thermal Mass: Dense rammed earth walls store and release heat slowly, which can moderate temperature swings in a building designed to use them. Performance depends on design, orientation, shading and climate.
- Fire Behaviour: Rammed earth walls are non-combustible. AS 3959:2018 accepts earth walls of 90mm or more up to BAL-FZ, though bushfire compliance for a whole building depends on the full project design.
- Acoustic Performance: The mass and density of rammed earth walls can provide strong airborne sound reduction. Where acoustic performance is critical, confirm project requirements with an acoustic consultant.
- Aesthetic Appeal: Each wall is unique, showcasing natural textures and colours that blend seamlessly with the environment.
Choosing rammed earth means investing in a home that's durable when properly designed and maintained.
Technical Specifications: Stabilised Rammed Earth
For architects, engineers, and builders, stabilised rammed earth (SRE) offers a robust construction solution.
Material Composition:
- Soil Mix: Designed per source material and tested for grading and plasticity. Cement content is typically 5–10%, set per project by the mix design and engineer. Other stabilisers, such as lime, alone or with cement, can be considered on a project basis, depending on the soil and the wall's exposure and detailing, under engineering and geotechnical guidance.
- Density: Material is placed and compacted in controlled lifts, with batching and construction records maintained throughout the build.
Structural Properties:
- Compressive Strength: HB195's recommended minimum for rammed earth is 2.0 MPa. We aim well above it, with a usual target of 3.0–5.0 MPa, adjusting the mix and testing through an independent laboratory until the project's criteria are met. The engineer confirms the criteria for each project.
- Wall Thickness:
- Standard: 300mm for load-bearing walls. Other thicknesses are possible subject to engineering design.
- Insulated Walls: Constructed to your engineer's specification, with the insulation product, thickness and R-value set by your engineer and energy assessor.
Performance Characteristics:
- Fire: Non-combustible. HB195 gives a general fire resistance level of up to 120/120/120 for earth walls meeting its minimum thickness. Any project-specific level is confirmed through the project's fire and engineering documentation.
- Acoustic: Strong airborne sound reduction from wall mass. Project-specific performance can be confirmed by an acoustic consultant.
Construction Process:
1. Formwork Setup: Custom-designed formwork is erected based on project specifications.
2. Mix Preparation: The soil mix is prepared with precise proportions of aggregates and stabiliser.
3. Layering and Compaction: The mix is placed in layers and compacted using pneumatic or electric rammers to achieve desired density.
4. Curing: Walls are allowed to cure, developing strength and stability over time.
We construct with reference to the Australian Earth Building Handbook (HB195) and AS 3959:2018 for construction in bushfire-prone areas.
FAQs
Facts & Questions About Rammed Earth
A smart, natural building material—timeless in look, modern in performance.
Click a question below to learn more.
1. Design & Aesthetic FAQs
What is Stabilised Rammed Earth (SRE)?
Stabilised rammed earth is a method where layers of earth—sand, gravel, clay, and a small amount of cement—are compressed in place to form strong, thermal, and striking walls. It's where ancient technique meets modern performance.
Can I have curved rammed earth walls?
Yes. Curved rammed earth walls are possible and need purpose-designed formwork and early coordination with your architect and structural engineer. The results are unique and visually striking.
What finishes are available?
Walls are often left raw to showcase their natural texture and layered tones. However, they can be sealed, burnished, or tinted with oxides for a customised finish. Each wall is unique—no two are the same.
2. Performance FAQs
How do rammed earth walls perform thermally?
Rammed earth provides excellent thermal mass but limited insulation. A solid wall isn't a substitute for insulation, so energy compliance is assessed per project by your architect or energy assessor. We construct insulated walls to your engineer's specification, with the insulation product, thickness and R-value set by your engineer and energy assessor.
Are rammed earth walls fire-safe?
Rammed earth is non-combustible. AS 3959:2018 accepts earth walls of 90mm or more up to BAL-FZ, but bushfire compliance for the whole building depends on the complete design, including openings, joints and penetrations. For fire separation, HB195 gives a general fire resistance level of up to 120/120/120 for walls meeting its minimum thickness, and any project-specific level is confirmed through the project's fire and engineering documentation.
Are they termite-resistant?
Termites can't eat rammed earth, but termite protection is still required for the building, as specified by your builder and certifier.
Do the walls need sealing or maintenance?
Yes. All wall faces are sealed with a breathable dust-binding and water-repellent sealer system, and uncapped wall tops receive a silane treatment. Resealing intervals depend on exposure, and we provide maintenance guidance at handover.
What's the lifespan of a rammed earth wall?
Well-built rammed earth walls can last well over 100 years. Globally, many historical examples have lasted for centuries. It's a legacy material with modern benefits.
Is rammed earth sustainable?
Rammed earth is made from natural mineral materials, often sourced locally, and can last a very long time when properly designed and maintained.
3. Construction & Practical FAQs
How thick are rammed earth walls?
- 200mm – Internal or non-load-bearing (other thicknesses are possible subject to engineering design)
- 300mm – Standard load-bearing wall
- 400mm+ – Insulated walls, built to your engineer's specification
Can electrical and plumbing services go through rammed earth walls?
Yes. All conduits and pipes are planned in advance and integrated during the wall-building process. There's no need for chasing or cutting after construction.
Are rammed earth walls waterproof?
While not inherently waterproof, external walls are sealed with breathable products that allow vapour to escape while protecting against water ingress. Correct roof overhangs and detailing are also essential.
Is rammed earth more expensive than traditional construction?
Upfront costs can be higher than many standard brick or timber walls, although premium bricks and timbers can cost as much or more. Benefits such as thermal mass, a unique aesthetic and long life can offset some of that over the life of the building.
Still Have Questions?
We’d love to talk. Whether you’re just exploring ideas or ready to build, we’re here to help.
[Contact us] or [Explore our Projects] to see rammed earth in action.