Insulated Rammed Earth: What is SIREWALL?

SIREWALL, is a structural wall system typically 18″ to 24″ thick, stabilized with compacted earth and rebar, with 4″ of rigid insulation hidden in the centre of the wall. Eye-catching, the SIREWALLS are a complete wall system with the strength and beauty of sedimentary sandstone. This distinctive, visceral connection to the earth is also the exterior and interior finish of a SIREWALL building – no sealants, siding or drywall required.  These high performance walls are constructed with a system backed by over 20 years of R&D, producing thermal mass and efficiency beyond any other wall system. This combination, along with the SIREWALL® System for quality control and soil blending, builds walls that exceed current standards for energy efficiency and compressive strength. The SIREWALL System has been refined over the last twenty years by SIREWALL’s expert builders, work seamlessly with unique designs and modern finishes that have timeless appeal.

SIREWALL has been the technological leader of insulated rammed earth since its invention in 1992 and was the only practitioner for the first thirteen years. SIREWALL has three patents issued and one patent pending on the specific technology that leads the way in thermal and structural excellence in this emerging industry.

SIREWALL System

The SIREWALL System starts with secured reusable forms that are filled with a mixture of damp earth. The soil blend, once compacted, creates structural rammed earth walls that will last several lifetimes without the need for maintenance.

SIREWALL Earth Masons use SIREWALL’s world leading soil blending technology to achieve the optimal blend for the project’s strength and texture requirements.  We can create almost any colour desired, and do have recommendations to achieve quality and economy on a project specific basis.  SIREWALL Base Admixture is used to limit efflorescence and for its hydrophobic properties.  The hidden core of insulation at the center of the wall is most typically (but not necessarily) polyisocyanurate foam.  Forming, delivery, and mixing are determined specific to the project.  Pneumatic and hand tampers are selected specific to the project.

Ongoing Research and Development

While most people are drawn to SIREWALL by its beauty, they may not realize that this inherent beauty is actually the result of over 20 years of investment in R&D. To improve functionality, the strength of Stabilized Insulated Rammed Earth needs to be so much higher than its uninsulated cousin, so we continually refine our Standards to ensure superior strength and performance. Our Standards are the highest, and we ensure SIREWALL Earth Masons, professionals who are the trained more than any other in the industry, meticulously follow them.

Green Building enthusiasts inspired to break ground and build a rammed earth structure with the best of intentions may be missing key components to create healthy, energy efficient homes and buildings that will last for future generations. Here’s a comparison chart that illustrates how depth of experience can result in a more solid approach to rammed earth construction.

 

Rammed Earth

Stabilized Rammed Earth

Non-Standard
Insulated Rammed Earth

SIREWALL Stabilized
Insulated Rammed Earth

Compressive Strength 1mPa – 3mPa
145psi – 435psi
3mPa – 7mPa
435psi – 1,015psi
3mPa – 28mPa
435psi – 4,060psi
20mPa – 30mPa
2,900psi – 4,350psi
R-value (static) R6 R6 R12 – R25 R33 & UP
R-value (dynamic) R9 – R13.5 R9 – R13.5 R38 – R56 R50 – R74
Erosion Resistance A garden hose erodes this Garden hose resistant Widely variable 2,500psi pressure washer resistant
Quality Control Protocol Unlikely Possible Unlikely Yes
Risk of efflorescence Possible Possible Possible Unlikely
Curing Protocol No Possible Possible Yes
Air barrier detailing No No Possible Yes
Pre-build soil optimization No Unlikely Minimal Yes
Vapour drive barrier No No Unlikely Yes
Engineer and Building Permit friendly No Yes Unlikely Yes
Large project capability Possible Possible Unlikely Yes
Standards & Specifications No Yes Variable, Self -monitored Yes
Possible patent infrigement No Yes Yes No
Results may vary. Matrix compares typical 2,500 square foot, two-storey home.

SIREWALL Cutaway

  • A. Rubble trench – 4 inch bed of drain rock
  • B. Reinforced concrete footing – up to 6 feet wide
  • C. Drain pipe
  • D. Interior rammed earth wall, reinforced with steel rebar
  • E. 4″ foam insulation
  • F. Exterior rammed earth wall, reinforced with steel rebar
  • G. EMT pipe to function as electrical conduit
  • H. Wooden top plate, anchored to wall, ready for roof truss
  • I. Interior floor
  • J. Optional anti-graffiti coating

What’s not visible in the diagram – How the strength of a stabilized, insulated rammed earth wall can vary when constructed. Depending on how a rammed earth wall is built, these factors can dramatically affect overall strength and durability:

  • Too much or little moisture – 40% difference, best to worst
  • Hand tamping or wrong tampers – 50% difference
  • Curing – 50% difference
  • Mixing – 75% difference
  • Pneumatic tamping or wrong tampers – 25% difference
  • Control of lift depth – 50% difference
  • Material management – 30% difference
  • Consistency of soils used – 25% difference

The SIREWALL System uses a proven series of protocols to consistently achieve the highest possible wall strength.

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