Building physics
of hemp limestones
The all-rounder for healthy demands
Thermal insulation
Der Isohemp Hanfstein hat eine Dämmwirkung, die modernen Baustoffen entspricht. Mit einer Wärmeleitfähigkeit λ von 0,071 W/m²K braucht der Hanf-Kalkstein sich nicht vor Konkurrenzprodukten zu verstecken.
Because of its good insulating properties, hemp-limestone can be used for modern new buildings. A timber frame wall, infill with a 30 hemp-limestone, achieves an insulation value of 0.23 W/m²K. The current EnEV stipulates a U-value of 0.24 W/m²K for extensions to an existing building.
Im Neubau wird für ein KfW 55-Haus ein Mindestwärmeschutz von ~0,20 W/m²K gefordert. Dies kann mit einem 38er Stein plus 24 mm Holzweichfaserplatte als äußerer Abschluss erreicht werden.
In timber frame renovation, the hemp-limestone can be used very well for the interior insulation of an existing timber frame wall. 120 mm hemp-limestone provide a better insulation value than interior insulation with 160 mm light clay. Due to the high moisture absorption and the good protection against mould provided by the lime, the hemp-limestone is ideally suited for historical building fabric.
Sound insulation, diffusion of sound
The inhomogeneous hemp fibre mixed with the mineral lime binder creates very high sound insulation. Thus, partition walls between two rooms can achieve a sound reduction of 57 dB.
For partition walls between two residential units, sound insulation can be further improved by a two-layer, decoupled construction.
Non-toxic, non-flammable, mould-inhibiting
Hemp does not need any pesticides, fertilisers or much moisture in cultivation.
Hemp is a historical cultivated plant with the lowest demands on soil and nutrient supply.
By mixing it with lime, the resistant hemp fibre becomes an even more stable building material. This hemp limestone is not combustible!
As a fibre, hemp absorbs an extremely high amount of moisture without feeling wet at all and without losing its insulating effect. The moisture can be quickly released back into the room air. The hemp-limestone is very mould-inhibiting due to the lime and the high moisture resistance of the hemp.
