Comfortable, healthy and robust buildings delivered with Hiberna Modular structural straw panels.
Sustainably designed and manufactured in Wanaka, NZ.
High-performance prefabricated straw panels, the smart building alternative
We’re all about creating healthier, affordable and more sustainable buildings.
Our structural straw panels offer a natural, eco-friendly alternative to traditional timber framing—designed to be strong, efficient, and planet-friendly.
From the energy-saving design of our modular building panels to the low-carbon materials we use, reducing our environmental impact is at the heart of everything we do.
Our systems are not only highly insulated and structurally solid, but also quick to install and cost-effective. Each panel is custom-made to fit walls, roofs, and suspended floors for both residential and commercial projects, making them a smart choice for any build.
Designed for healthy, comfortable living
We care about the well-being of people and the planet, crafting buildings that are as healthy and comfortable as they are eco-friendly.
Our prefabricated straw panels bring a sense of harmony and wellness to every space by maintaining high indoor air quality, consistent temperatures, and a quiet, serene environment.
Plus, they’re easy to integrate into any modern home build or even the most ambitious architectural design.
Thanks to their airtight, well-insulated design, our buildings use less energy to heat and cool, making them a smart and sustainable choice all around.
Specifications
Highly insulating locally sourced, compressed straw (and optional wood fibre board). R Value 5-8 depending on product.
Acoustic baffling, naturally integrated through insulation properties.
Versatile use with any external cladding where a cavity exists, or opt for a lime/lime stabilised earth plaster. We can supply these in bulk pre-mixed (*some design requirements existing for external plaster finishes.)
Designed for comfort with panel thickness at 270-430mm (vs. 90mm or 140mm – standard house), our panels provide comfort, no matter the conditions.
Want more technical information and specifications on our panels? Download our information brochure.
Locally sourced materials sourced entirely from the lower south island reducing carbon miles.
Low carbon our construction method uses around half the carbon of standard construction and helps to store huge amounts from the atmosphere.
Cost effective double the wall width at a similar price to 140mm timber framing (with batts.) No gib stopping or painting required.
Time efficient manufactured offsite, incorporating proprietary fittings designed to improve build/ fit time once on the slab.
From design to build, our sustainable construction systems are just better
Our driving belief is that buildings should be as sustainable as they are beautiful. Our custom panels are innately strong and versatile, helping architects bring their energy-efficient, durable, and stunning designs to life.
We’re also paving the way for a greener, faster, and more cost-effective approach to construction. By sourcing materials locally and manufacturing off-site, we keep our carbon footprint low and minimise waste.
Our pre-assembled SIPs arrive on-site precisely cut and ready to install, making the process quicker and smoother. Plus, they reduce the need for specialist labour, unlike traditional framing methods—saving builders time and hassle.
Carbon-locking in the benefits
Our structural panels are made from wood and compressed straw, low-carbon materials that absorb huge amounts of carbon dioxide during growth.
Each Hiberna Modular straw panel stores four times more carbon than is emitted during production and emits just half the carbon of a typical timber frame wall – helping reduce New Zealand’s carbon footprint today, not decades from now.
FAQs
Is continuous and adequate ventilation recommended for buildings with straw insulation?
Continuous mechanical ventilation appropriate for the occupancy is strongly recommended because modern, well-sealed buildings, especially with high internal occupancy levels.
Ventilation rates should meet or exceed building code requirements (e.g., NZBC's 0.35 ACH or 7.5 L/s per person minimum), as these rates significantly impact internal moisture, comfort levels and loads on the building enclosure.
What is hygrothermal analysis?
Hygrothermal analysis, typically using WUFI software (Wärme- und Feuchtetransport instationär) is used to analyse heat, air, and moisture (HAM) transport in building components and assemblies. It is indispensable for accurately predicting the long-term durability of moisture-sensitive materials like the straw within the Hiberna Modular system.
Accredited WUFI analyses for comparable straw panel systems, such as EcoCocon, demonstrate no long-term moisture accumulation, even under stress-test conditions. These analyses show that the straw panel layers dry out quickly, maintaining moisture content consistently below critical limits for mould growth. Hiberna Modular has used WUFI simulation to model how it performs in a number of locations around the country. The modelling is project-specific, so we might recommend modelling for your project as a way of verifying for a building consent application.
What Sound Transmission Class (STC) or weighted sound reduction index (Rw) values are typically achieved by comparable plastered straw bale walls and panels?
Reported Rw values for plastered straw bale external walls typically range from 43 to 59.4 dB. Comparable systems like EcoCocon panels achieved an Rw rating of 54 dB, which is considered excellent for typical wall assemblies and suitable for various building types requiring significant noise reduction.
What are the acoustic insulation capabilities of the Hiberna Modular wall panel system?
Our wall panel system offers strong acoustic insulation capabilities, contributing significantly to occupant comfort, privacy, and noise reduction. The inherent density and thickness of straw bale walls contribute to their sound insulation properties, aligning with the principle that mass is a primary factor in blocking sound.
What do accredited test results indicate about VOC emissions from straw-based building materials?
Accredited test results for VOC emissions from various building materials, including straw products, consistently show very low levels of Total VOC (TVOC), Total Semi-Volatile Organic Compounds (TSVOC), and specific carcinogens like formaldehyde. These tests frequently report emission levels below quantification limits, indicating minimal release of harmful substances.
How does the Hiberna Modular wall panel system contribute to healthy indoor air quality?
Our wall assembly proactively promotes a healthier indoor environment by prioritising naturally sourced, low-toxicity materials. Its primary components—straw, clay, and lime—are inherently safe and free from Volatile Organic Compounds (VOCs) and formaldehyde, which can off-gas from many conventional building materials.
This directly contributes to superior indoor air quality from the very first day of occupancy.
What U-values and R-values are typically achieved by comparable straw panel systems?
R-values for straw bale walls typically range from 5.3 to 7.0 (m2K/W). Comparable systems like EcoCocon panels achieve declared U-values as low as 0.12 W/(m2K) for a complete system with clay plaster, and even 0.106 W/(m2K) with increased insulation thickness. The Hiberna system itself claims a U-value in the range of 0.12−0.15 W/(m2K) ( ~ R 1.9/100mm)
What are the key benefits of the Hiberna Modular system regarding thermal performance and energy efficiency?
The system, with its compressed straw core, achieves exceptional U-values, leading to a dramatic reduction in both heat loss and heat gain, resulting in consistent indoor comfort and significantly lower energy bills. It prioritises the elimination of air gaps and thermal bridges for optimal thermal performance and contributes to overall airtightness. Straw at 105 kg/m3 is conservatively R1.9 per 100mm.
What are the racking shear and compression strength capacities observed in comparable straw panel systems?
Plastered straw bale walls have shown effective performance against wind loads, resisting up to 2.4 kilopascals (kPa).
Studies on prefabricated straw-bale panels reveal significant improvement in stiffness and resistance with the complete rendered panel, sustaining loads far exceeding those of bare timber frames or straw-filled panels alone. Full-size plastered straw bale walls reinforced with wire mesh have achieved ultimate shear capacities of 67.1 kilonewtons per meter (kN/m).
Regarding vertical loads, plastered straw bale prisms show a maximum average compressive strength of 0.98 N/mm2 with a 20mm plaster thickness. EcoCocon panels have declared characteristic vertical load-bearing capacities of 60.0 kN/m without struts.
How does your wall panel system achieve structural integrity, particularly concerning racking shear and compression strength?
The Hiberna Modular system functions as an engineered composite structure where the synergistic interaction of the straw infill, the interior and exterior lime plaster skins (which contribute as structural skins), and structural timber framing. This allows the wall to effectively resist both lateral and vertical loads. Bracing is incorporated where required with an integrated diagonal tensioned 10mm metal rods.
What Fire Resistance Ratings (FRR) and Reaction to Fire Classifications have comparable plastered straw panel systems achieved?
General plastered straw bale walls have achieved an FRR of 120-135 minutes (REI 120-135) for non-load bearing elements and 2 hours for structural integrity under ASTM E119.
Comparable systems like EcoCocon panels achieved an REI 120 rating and a B-s1, d0 classification according to EN 13501-1 for both internal and external surfaces, indicating very limited contribution to fire, weak or absent smoke production, and no flaming droplets.
What contributes to the exceptional fire resistance of your wall panel system, especially given that raw straw is combustible?
The high density of compressed straw within the panel core limits oxygen availability, causing tightly packed straw to smoulder rather than rapidly ignite. Lime plaster, a mineral-based material, is naturally fire-resistant, does not catch fire or spread flames, can withstand temperatures over 500 degrees Celsius, and releases carbon dioxide when disintegrating, which helps extinguish fires.
Importantly, it does not produce toxic fumes or smoke when burned. The exterior plaster layer incorporates borax, which, when exposed to heat, forms a protective vitreous layer and promotes a carbonaceous char, slowing pyrolysis and suppressing flame combustion and smoke formation.
How does your wall panel system utilise hygrothermal analysis?
The application of hygrothermal analysis, typically using WUFI, is indispensable for predicting the long-term durability of moisture-sensitive materials like the straw within the Hiberna Modular system.
Accredited WUFI analyses for comparable straw panel systems, such as EcoCocon, demonstrate no long-term moisture accumulation, even under stress-test conditions. These analyses show that the straw panel layers dry out quickly, maintaining moisture content consistently below critical limits for mould growth.
Why is hygrothermal analysis, such as WUFI, recommended for designing and assessing risk in straw insulation buildings?
Hygrothermal modelling tools like WUFI Pro 6 and WUFI VTT are superior to simpler models because they allow for one-dimensional analysis of coupled heat and moisture diffusion, and capillary effects through building assemblies, accounting for material moisture buffering and non-linear humidity distribution.
These tools can also simulate mould growth risk based on Viitanen's mould model, with the mould index ideally not exceeding 1.0 on exposed interior surfaces and not exceeding 3.0 on any internal surface. Analysis should account for potential variations in natural material properties and be performed for critical orientations and appropriate weather data.
What role does ventilation play during the construction phase of straw insulation buildings?
Continuous ventilation (exceeding 0.5 ACH for the entire building) should be maintained during construction, even before mechanical ventilation systems are commissioned, using fans or open windows.
Why is continuous and adequate ventilation crucial for buildings with straw insulation?
Continuous mechanical ventilation appropriate for the occupancy is strongly recommended because modern, well-sealed buildings, especially with high internal occupancy levels, are risky without assured ventilation.
Ventilation rates should meet or exceed building code requirements (e.g., NZBC's 0.35 ACH or 7.5 L/s per person minimum), as these rates significantly impact internal moisture levels and loads on the building enclosure.
How does the Hiberna system avoid issues with vapour barriers and coatings?
Its design philosophy emphasises "breathability" and vapour permeability. Both its interior and exterior lime-stabilised earth plasters and the straw panel core are highly vapour-permeable.
This approach allows moisture to easily diffuse through the wall, distinguishing it from conventional walls that might trap moisture.
Should vapour barriers be used with straw insulation, and what are the risks associated with certain coatings?
Be cautious with internal surface coatings, and avoid vapour barriers. While a normal roller-applied interior paint can reduce moisture at the surface, additional vapour resistance on the outside of the straw (like a lower permeability WRB or cementitious render) combined with lower vapour resistance straw or internal plaster can lead to failure of mould criteria.
What is the recommended permeability for the Water Resistive Barrier (WRB) when building with straw insulation?
The WRB needs to have as low permeability as possible to prevent moisture ingress from the exterior while still allowing drying.
How does the Hiberna system utilise permeable plasters for moisture management?
The Hiberna system incorporates a 30mm layer of lime-stabilised earth plaster on the interior and a 10mm layer of lime-stabilised earth plaster on the exterior of the compressed straw core.
Both of these plaster layers are highly vapour-permeable, facilitating the diffusion of moisture through the wall assembly and its escape to the outside via the ventilated cavity.
What role do permeable plasters play in straw insulation construction, and what types are recommended?
Permeable plaster skins (typically 20 to 60mm thick) are vital to allow moisture to escape from the straw bales. Increasing lime content in stucco mixes enhances vapour permeance, with pure lime-sand stuccos being among the most permeable.
Pure cement-sand stuccos are highly vapour-resistant and should be avoided.
A proposed assembly includes a 10mm thick clay slip layer sprayed onto compressed straw, followed by a 20mm lime-stabilised earth plaster and an 8mm internal lime plaster, all chosen for appropriate vapour permeability.
How does your wall panel system address moisture management and weather tightness?
Our system employs a multi-layered defence. The outermost cladding provides the primary defence against bulk water. Behind this, a ventilated cavity acts as a rapid drainage plane and promotes continuous drying. A breathable building membrane is installed over the exterior plaster for temporary weather protection and as a continuous moisture barrier.
The 10mm exterior lime-stabilised earth plaster acts as a moisture buffer and a vapour-open membrane, allowing the wall to breathe outwards. Both the interior (30mm) and exterior (10mm) lime-stabilised earth plasters, along with the compressed straw core, are highly vapour-permeable, allowing incidental moisture to diffuse and escape, preventing accumulation and inhibiting mould growth.
What are considerations for robust moisture control and protection when building with straw insulation?
Preventing water intrusion through a robust building envelope design, including proper flashings and detailing for external moisture features, is paramount.
Additionally, protecting straw bale wall segments from rain during construction until they are under a roof and the Water Resistive Barrier (WRB) is weathertight is crucial.
Avoid closing up the building during construction to prevent condensation and ensure materials like timber are dried to below 12% average moisture content before insulation or interior lining is installed. Sufficient ventilation and time for interior plaster and concrete to dry are also necessary before sealing the building.