Hemp for building: what to choose and why
Twelve hemp manufacturers. Eight say they hold a verified environmental declaration, we hold the document for six, and for two of those six the document isn't theirs but their block supplier's. Even so it is one of the best ratios in the directory: in hemp the figure usually exists, which lets you choose on data rather than on faith.
This guide covers blocks, mortars and insulation. They are different products that share a plant and little else, so the picks go by use.
How we chose
We only feature products with their own third-party verified environmental declaration that we have read and whose validity we know. While checking this guide we withdrew two picks: one rested on a calculation report that is not an EPD, and the other had a negative footprint on its entry that its own declaration contradicts. Both entries are now corrected.
We check the declared unit. In hemp, figures per square metre of wall, per cubic metre and per kilo sit side by side, and only those sharing a unit are comparable.
And we read conductivity together with density, because a hemp block and a hemp insulation share a name and not much else.
No company pays to appear here or to be picked. The selection is not for sale. How we measure →
Our picks
- Our pick for insulation
Ekolution
Its own declaration, valid to 2028: −6.81 kg CO₂e per square metre at 100 mm, with 0.04 W/m·K and 35 kg/m³ declared.
View entry → 
For blocksCânhamor
Three declarations of its own, one per thickness, valid to 2029. The 20 cm block declares −7.83 kg CO₂e per square metre of wall, adding the fossil carbon it emits and the biogenic carbon it stores.
View entry →
Compare the data
| Material | Footprint A1–A3 | Conductivity λ | Density | Verified EPD |
|---|---|---|---|---|
| Von Hanf | -77,4 kg CO₂e/m³ | 0,04 W/m·K | 300 kg/m³ | No |
| Cânhamor | -25,083 kg CO₂e/m³ | 0,069 W/m·K | 318 kg/m³ | Yes · document |
| HEMPCRETE SPAIN | 102,478 kg CO₂e/m³ | 0,06 W/m·K | 200 kg/m³ | Yes · document |
| ISOHEMP | 102,478 kg CO₂e/m³ | — | — | Yes · document |
| Ekolution | -6,81 kg CO₂e/m² | 0,04 W/m·K | 35 kg/m³ | Yes · document |
| HempFlax Building Solutions | -2,436 kg CO₂e/m² | — | — | No |
| Saint Astier | 1,89 kg CO₂e/m² | — | — | Yes · document |
| Hemp Block UK | 8,07 kg CO₂e/m² | 0,07 W/m·K | 330 kg/m³ | Yes · document |
| Bloque de cáñamo Cannabric | — | 0,19 W/m·K | 1300 kg/m³ | No |
Only materials with some published data are listed, ordered by footprint within each unit. Two footprints declared in different units are not comparable with each other. «Yes · document» means we hold the declaration and the figures come from it; «Declared» means the manufacturer says it has an EPD but we don't hold the document, and its figures come from the entry. A dash means the manufacturer doesn't publish it, not that the material lacks it.
Everything else
Bloque de cáñamo Cannabric
Pionera española en bloques de cáñamo y cal (hempcrete) para bioconstrucción.
Cânhamor
Bloques de hempcrete (cáñamo + cal) 100% naturales y carbono-negativos. Primera fábrica del mundo con ciclo completo de producción.
Cavac Biomatériaux – Biofib
Aislamientos Biofib de cáñamo y lino cultivados a menos de 100 km de la fábrica, con FDES en INIES.
Edilcanapa
Empresa italiana especialista en construcción con cáñamo y cal. Materiales naturales para aislamiento.
Ekolution
Aislamiento de fibra de cáñamo sueco, carbono-negativo y energéticamente eficiente.
Hemp Block UK
Bloques de cáñamo y cal de alta densidad para cerramientos y aislamiento, con EPD verificada y huella de carbono negativa.
HEMPCRETE SPAIN
Material de construcción cáñamo-cal con capacidad de secuestro de CO2, transpirable y aislante térmico.
HempFlax Building Solutions
El mayor productor europeo de cáñamo industrial fabrica aislamiento Thermo Hanf de la semilla al panel.
Hempitecture
HempWool: la primera EPD de aislamiento de cáñamo de EE. UU., con huella de fabricación negativa.
ISOHEMP
Fabricante industrial de bloques de cáñamo-cal 100% natural. Produce >1M bloques/año, Bélgica.
Saint Astier
Cal hidráulica natural NHL producida en Francia desde 1851 (grados NHL 2/3.5/5) + nueva gama de morteros con cáñamo, corcho y vidrio reciclado.
Von Hanf
Sistema constructivo integral de cáñamo alemán: bloques estructurales, paneles acústicos y sustitutos del pladur que secuestran carbono.