Product research profile
A hemp-based interlocking block wall system, made in Europe and sold in Australia, offered as an alternative approach to building envelopes and insulation.
Hemp walls are widely discussed for their carbon and comfort potential. This profile sets out what is documented for this product, what is only studied for hempcrete in general, and what is still to be confirmed.
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Circular Abundance research assessment
A short summary of this profile. It describes the state of the evidence and does not score or rank the product. Commercial maturity and evidence quality are separate: one describes the market, the other how much independent evidence supports the product. Both are defined on our evidence page.
Emerging commercial solution
Sold commercially in Australia and New Zealand, with a CodeMark certificate (CM40371) and a training course. We label it emerging because the certificate's stated expiry (29 September 2026) has passed and we could not confirm renewal, no product EPD or independent test data were found, the product is imported, and the Australian project record is not documented.
Partly verified
One independent element: a CodeMark certificate (CM40371) issued by an accredited certification body, covering stated National Construction Code provisions within a stated scope. Its stated expiry (29 September 2026) has passed and we could not confirm renewal. Weatherproofing is not assessed and structural adequacy of the wall's fire rating is outside the certificate. The test reports it cites were not read. No product EPD was found, and thermal, speed, termite and cost statements elsewhere are the company's own.
No product EPD or product-specific life-cycle assessment was found. Peer-reviewed studies of hempcrete in general report that carbon outcomes depend on mix, carbonation and transport.[1][2] Whether HempBLOCK is net carbon-negative is not demonstrated.
Manufactured in Europe (the licensor is Vicat and the maker is reported to be Vieille Matériaux), with shipping of 6 to 8 weeks to Australia. Australian and US manufacturing is planned, not current.[3][4]
Historical information: a CodeMark certificate (CM40371-I01-R00, CMI Certification, issued 29 September 2023) is published on the certification body's register. It lists the holder as GeoSIP Pty Ltd trading as HempBLOCK Australia Pty Ltd, covers building classes 1 to 10, wind classes N2 to N4 and wall heights to 2.9 m, and cites a fire test result of -/60/60 (integrity and insulation), a dry thermal resistance of 4.61 m²K/W at 300 mm and a sound rating of Rw 43.[5][6] Its stated expiry is 29 September 2026, which has passed, and we could not confirm renewal, so current certification status is unconfirmed.[5][7] An expired or unconfirmed certificate does not by itself mean the product is non-compliant; it means current compliance evidence has not been confirmed. The certificate excludes weatherproofing and structural adequacy of the fire rating, and does not state a number of storeys.[5] Termite statements are the company's own.
No verified cost. Speed claims range from half the time to up to 60% or 70% faster and none is independently measured.[8][3][4] A fair comparison must include the frame, freight and render.
No end-of-life pathway is documented for the product. Hemp and the natural binder are mineral and plant materials, but the key LCA studies either omit end of life or note limited data.[2][9]
Editorial perspective · Our interpretation
Interlocking hemp blocks address the main drawback of site-mixed hempcrete, which is slow, skilled work, and a post-and-beam frame gives a clearer structural pathway. If the certificate is current and the underlying test data hold up, HempBLOCK could make a bio-based wall practical for homes, and the general research on hemp walls is encouraging.
The case for this product rests on a CodeMark certificate whose stated expiry has passed, general research on hempcrete, and company statements. The blocks are imported, no EPD exists, and cost and speed claims are untested. It is a promising approach, and its carbon, fire and cost claims should be confirmed against current documents before they are relied on.
Each row shows the class of source behind it, so claims can be weighed appropriately.
| Origin & manufacture | Sold by Queensland-based HempBLOCK Australia; blocks made in Europe under licence from the Vicat group.[3][4] | Trade / media |
|---|---|---|
| Category | Walls & Cladding · Insulation & Thermal Performance · Recycled & Renewable Materials | Our note |
| Product type | Interlocking hemp-and-binder blocks for walls: load-bearing LB 300 around a steel and concrete frame, and mortared non-load-bearing HB Series.[10] | Manufacturer |
| Material | Stated 84% hemp shiv with a natural cement binder.[8] | Manufacturer |
| LB 300 block | 600 × 308 × 300 mm; 18 kg.[10] | Manufacturer |
| Scale | Certificate scope: building classes 1 to 10, wind N2 to N4, walls to 2.9 m, no storey limit stated.[5] Trade press says single-family homes and up to two storeys.[11] | Third-party verified |
| Certification | Historical: CodeMark certificate CM40371 (CMI Certification, issued 29 Sep 2023, stated expiry 29 Sep 2026). Current certification status: unconfirmed.[5][7] | Third-party verified |
| Environmental declaration | None found. | Our note |
| Supply | Imported from Europe; 6 to 8 weeks shipping.[3] | Manufacturer |
HempBLOCK is an interlocking wall system built from pre-formed blocks of hemp shiv bound with a natural cement. The load-bearing version, the LB 300, is a mortar-free block stacked around a steel and concrete post-and-beam frame; a second, mortared range is for non-load-bearing walls.[10] The blocks are made in Europe and sold in Australia through a Queensland-based company.[3][4]
Hemp-based walls attract interest for their low-carbon and breathable qualities, and interlocking blocks aim to make them quicker to build. This profile is more cautious than most coverage. We found no Environmental Product Declaration for HempBLOCK, the Australian CodeMark certificate has a stated expiry that has passed, and most performance statements outside it are the company's own.
The LB 300 system is a frame-and-infill approach. A steel and concrete post-and-beam frame carries the structural load, and the hemp blocks interlock around it without mortar, forming the insulating and finishing layer of the wall.[10][4] Walls are then reinforced and rendered, and can be clad or plastered.[3][8]
| Product | Dimensions | Intended use (manufacturer) |
|---|---|---|
| LB 300 interlocking block (standard, column, double column, U / lintel / bond beam) | 600 L × 308 H × 300 D mm; 18 kg (39 lb) per block | Mortar-free blocks that encase a post-and-beam load-bearing system; load-bearing and infill walls, residential and commercial.[10] |
| HB Series (HB100, 150, 200, 300) | 600 mm long; 100, 150, 200 or 300 mm deep | Mortared, non-load-bearing; veneer for internal partition or infill walls.[10] |
| Lime mortar and lime render | 25 kg bags; render in 92 colours; one bag covers two coats on 0.9 m² | Used with the HB Series and to finish walls.[10] |
Arithmetic from the stated block size: a 600 × 308 mm face is 0.185 m², so about 5.4 LB 300 blocks make a square metre of wall, and the blocks alone weigh about 97 kg/m² (18 kg × 5.4). The frame, reinforcement and render are extra.[10]
We found no Environmental Product Declaration or product-specific life-cycle assessment for HempBLOCK. The company says hemp walls reduce heating and cooling energy and carbon emissions,[8] but the figures that would support that for this product were not found.
| Study | What was assessed | Finding and caveats |
|---|---|---|
| Arehart, Nelson & Srubar (2020), University of Colorado | Model of carbonation plus biogenic storage, applied to 36 hempcrete mixes; 1 m² wall at U 0.27 W/m²K | Carbonation recovered 18.5% to 38.4% of binder-production emissions. Total life-cycle emissions can be negative, to −16.0 kg CO₂e per functional unit, but not all mixes stored net carbon.[1][9] |
| Arrigoni et al. (2017) | LCA of a non-load-bearing wall of hempcrete blocks, excluding end of life for lack of reliable data | Negative carbon footprint driven by hemp growth and carbonation uptake; the paper analyses the role of carbonation, mix components and transport.[2] |
| Tam et al. (2025), Western Sydney, Newcastle and Melbourne universities | Cradle-to-grave comparison of walls on one single-storey home at Narara Ecovillage, NSW | The research portal reports 49.57 t CO₂e for hempcrete walls against 61.81 t for brick veneer, about 20% lower by our arithmetic. We could not confirm that HempBLOCK was the system studied, and the portal's own percentages do not reconcile with these totals, so treat the figures cautiously.[12] |
The table separates what the CodeMark certificate states from what the company and media report. The certificate was read through the certification body's register on 15 November 2026; the test reports it cites were not read. The certificate is shown as historical information. Its current status is unconfirmed, and nothing here should be read as saying the product is currently certified. An expired or unconfirmed certificate does not by itself mean the product is non-compliant; it means current compliance evidence has not been confirmed.
| Item | Reported | Source type |
|---|---|---|
| Building code (CodeMark) | Certificate CM40371-I01-R00 for HempBLOCK Wall Systems, issued 29 September 2023 by CMI Certification to GeoSIP Pty Ltd trading as HempBLOCK Australia Pty Ltd, against the 2022 National Construction Code. Stated expiry 29 September 2026; renewal unconfirmed.[5][13][7] Scope: building classes 1 to 10, wind classes N2 to N4, wall height to 2.9 m, bushfire BAL 12.5 to BAL FZ with conditions, installation to the manufacturer's manual by trained installers. Storeys are not stated. Exclusions: weatherproofing is not assessed, structural members need separate engineering, and structural adequacy of the fire rating is outside scope.[5] | Third-party verified |
| Fire, thermal, acoustic (as cited by the certificate) | Fire resistance of -/60/60 tested to AS 1530.4:2014 without the heat-flux measurement; dry thermal conductivity 0.0651 W/mK at 10 °C, giving 4.61 m²K/W at 300 mm (moisture would raise conductivity); sound rating Rw (C;Ctr) 43(-1;-2) for the tested wall system.[5] These values are quoted from the certificate; the test reports were not read. | Third-party verified |
| Overseas | The certifications page says hemp blocks are included in the ICC International Residential Code in the USA, citing Appendix BL Hemp-Lime Construction, and that European product certification equivalents are recognised internationally.[6] The appendix addresses hemp-lime construction as a method rather than certifying this product. | Manufacturer |
| Scale | The load-bearing LB 300 system is described as suitable for single-family homes and buildings up to two storeys.[11] The certificate does not state storeys, so check current design documents. | Trade / media |
| Fire | Described as fire-resistant, and as withstanding temperatures up to 300 °C without catching fire.[3][11] The certificate cites a tested rating (above), which is independent of the company's wording. A separate Tasmanian project had commercial fire testing for its hempcrete wall; that does not transfer to this product.[14] | Manufacturer |
| Thermal and moisture | Walls are described as hygroscopic, moving moisture to moderate humidity and temperature, with no need for additional battens or insulation.[8] The certificate cites a dry thermal resistance (above); moisture would raise conductivity and the LB 300 performance datasheet was not read.[15][5] | Manufacturer |
| Termites and mould | The alkaline binder is said to deter termites, and the lime-and-hemp matrix to prevent mould build-up.[8] No independent test was found. | Manufacturer |
| Documents available | Installation manual, LB 300 technical details and performance data, mortar and render datasheets, and a CodeMark document are linked from the manufacturer's site.[8] | Manufacturer |
What we could not verify. Whether the certificate is current, the underlying test reports, the LB 300 performance datasheet, and the certificate's own inconsistencies: it cites AS 4055-2012 in one table and AS 4055-2021 in its text, and gives the fire report date as both 25 October 2022 and 2 October 2022. The most useful next step is to ask the manufacturer for the current certificate and the test reports.
The LB 300 encases a steel and concrete post-and-beam system, so structural design comes first, with an engineer and the certificate's conditions in hand.[10][4]
Blocks arrive ready to use and interlock without mortar jointing.[4] The company says construction takes about 10 minutes per square metre.[8]
The blocks are reinforced and then rendered; walls can also be clad or plastered.[3][8]
The company runs a three-day Master Builder course for builders and owner-builders on installing the LB 300.[3]
No verified cost was found. The company offers an online materials and price estimator for projects,[8] but we have not tested it, and no independent comparison of a finished HempBLOCK wall with brick, timber frame or other systems was found.
We did not compile a list of completed HempBLOCK projects for this profile. The items below give context for hemp-based walls in Australia and are not endorsements of this product.
A lime-based hempcrete project described as the largest commercial use of hempcrete in Australia. The university says it obtained a commercial fire rating through testing commissioned for the project. This is a different hempcrete system, not HempBLOCK.[14]
A single-storey home used for a peer-reviewed comparison of hempcrete and conventional wall systems. It is not confirmed that HempBLOCK was the product studied.[12]
Verified Australian projects using the LB 300 or HB Series, with owner or builder confirmation and, ideally, measured performance.
As-built cost, build time, thermal performance and moisture behaviour in a humid climate.
Carbon claims for hemp walls rest on general studies, whose results depend on mix, carbonation and transport. None is specific to this product.[1][2]
The CodeMark certificate states an expiry of 29 September 2026, and a register search for the number returned no result on 15 November 2026. Renewal, replacement or lapse is unconfirmed. The certificate also excludes weatherproofing.[5][7] An expired or unconfirmed certificate does not by itself mean the product is non-compliant; it means current compliance evidence has not been confirmed.
Blocks come from Europe with long shipping times, and local manufacturing is only planned.[3]
Speed, thermal, fire and termite statements come from the company or media repeating it, and the speed figures contradict each other.[8][3][4]
The load-bearing system is a steel and concrete frame with infill blocks, so the whole-wall footprint and cost are not the block alone.[10]
Superscript numbers in this profile refer to the sources below, listed in the order they are first cited. The label on each shows the class of source and how much weight it deserves.
HempBLOCK International (Australia)
Sold in Australia and New Zealand by HempBLOCK Australia; blocks are manufactured in Europe.[3][4] Contact details as published on the manufacturer's website:[8]