LLS 400: Hemp-Clay Filling (semidry) - hempcob

Wall Insulation Filling

Therman Insulation and Heat Reservoir

  • LLS-400 is applied behind an open plaster base
  • 60 mm insulation thickness or more

First construct the substructure, suitable as plaster base. That substructure is mounted on a wall, or is a free standing construction (for partition walls). Usable are all common plaster base systems, such as rush mats, clay boards, wooden fibre boards, etc.

LLS-400 is filled layer by layer. No air pockets should remain inbetween the layers. The layers should have a maximum height of 15cm.

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  • use a brush to sprinkle LLS-400 with water
  • 3 ltr of water must be added per bag.
  • fill the construction layer by layer, each layer measuring 10 to 15 cm
  • moisten the layers
  • raise the plastering base to support the next layer of the filling
  • at the upper end and for connections to complex structures, LLS-400 is prepared with more water (earth-moist), which simplifies overhead application and filling of small, irregular gaps


  • hemp chippings
  • hemp fibers
  • clay powder (dried)
Bauphysikalische Eigenschaften
thermal diffusivity a = 0,111 mm²/s
static thermal conductance (static) λ = 0,074 W/mK
heat transfer coefficient (dynamisch) 1/b = 0,004 Wvs/m²K
specific heat capacity c = 1,5 kJ/kgK
fire protection class E (corresp. to B2)
diffussion coefficient µ = 4-5
density (dry) 420-450 kg/m³

Plaster or Insulating Plaster

Plaster is applied last, without any need to let the filling dry out. We recommend out hemp-clay insulation plaster HL-DU-04, but any DIN clay plaster or lime plaster is applicable.

An open plaster base, such as a 70-stalk rush mat, will let moisture diffuse into the fillinf. This is a desired effect! The moisture will (re)-activate the clay agglutanation, thus securing the structural stability for many years.

Integrated Wall Heating

Wall heating tubes are mounted directly on the resulting plaster base, witout any additional time needed to dry the filling. Application guidelines for the plastering of the heating tubes must be followed.

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