Thermal insulation

Hemp-lime blocks offer an insulating performance on a par with modern building materials. With a thermal conductivity λ of 0.071 W/(m·K), hemp-lime blocks easily hold their own against competing products. Some high-performance insulating vertically perforated clay blocks only achieve a U-value of 0.18 W/m²K.

Thanks to its good insulating properties, the hemp-lime block can be used in modern new-build construction. A timber-frame wall infilled with a 30 cm hemp-lime block achieves a U-value of 0.23 W/m²K. For extensions to existing buildings, the current EnEV (German Energy Saving Ordinance) specifies a U-value of 0.24 W/m²K  to be achieved.

In new builds, a minimum thermal insulation of ~0.20 W/m²K is required for a KFW 55 house. This can be achieved with a 38 cm block plus a 24 mm wood fibre insulation board as the external finish.

In the renovation of timber-framed buildings, the hemp-lime block is very well suited to the internal insulation of an existing timber-framed wall. 120 mm of hemp-lime block provides a better insulation value than internal insulation with 160 mm of light clay. Thanks to its high moisture absorption and the high pH value of the lime, which reduces the risk of mould, the hemp-lime block is ideally suited to historic building fabric.

Sound absorption, sound diffusion

The non-homogeneous hemp fibre, mixed with the mineral lime binder, provides a very high level of sound insulation. Partition walls between two rooms can thus achieve a sound reduction of 57 db.

For separating walls between two dwellings, sound insulation can be improved further with a two-layer, decoupled build-up.

Non-combustible,
highly alkaline

Hemp requires no pesticides, fertilisers or large amounts of water during cultivation.
Hemp is a historic crop with minimal demands on soil and nutrient supply.

Mixing with lime turns the resistant hemp fibre into an even more stable building material. This hemp-lime block is non-combustible!

As a fibre, hemp absorbs an extremely large amount of moisture without feeling wet at all and without losing any of its insulating performance. The moisture can be released back into the room air quickly. The high pH value of the lime and the moisture-regulating properties of the hemp-lime block reduce the risk of mould.