HDW Insultation Wool

Hemp-based Wool

  • material with controlled and standardized properites
  • thermal insulation for diffusion-open construction
  • sound absorbing and pollutant free

HDW Insulation Wool is usable for

  • roof insulation (peaked and flat roofs)
  • facade insulation (indoors and outdoors)
  • wood frame construction and attic insulation

HDW Insulation Wool is universally applicable, for new constructions as well as for improving insulation of older buildings.

  • very favourably priced
  • every nook and corner can be perfectly filled with the insulant,
  • no seems, folds or overlaps
Europaen technical approval ETA-01/0016
static thermal conductance λ = 0,045 W/mK
dynamic thermal conductance 0,91 m²/h
density 50 kg/m³
fire protection class C-s2,d0 (B1: flame resistant)
acoustic absorption at 4 cm insulation thickness a = 0,55 (H)
aerodynamic resistance 1,2 kPas/m²
humidity absorption 3,89 kg/m²
diffussion coefficient µ = 1-2

The HDW stuffing-wool is delivered in lightly compressed bales of approx. 30 kg.
Before application, the wool's natural structure is recovered by relaxation. To achieve that, the bales are opened one or two days before processing.
For optimal conditioning, the wool should be turned over once during that resting period. The density after application varies between 50 and 55 kg/m³.

  • all spaces, including corners and nooks, need to be carefully filled
  • always stuff without strength

Comparison to insulation fleece

The application of insulation fleeces results in approx. 20% waste (for insulating old roofs), as distances between roof beams, windows and other boundaries rarely correspond to the dimensions of the fleece. The use of wedges reduces that to about 15%, but even for new constructions, 10% of the material are commonly wasted.

The use of insulation wool leaves no waste, and no special-purpose tools are needed either (which for fleeces can amount to additional 300-350 €). Insulation wool can be applied by non-professionals without training, handling is simple and secure.

Recommendation for roof insulation:

  • mount external battens onto the roof beams, with standard spacing (depending on the constraints of the roofing material)
  • apply HDW insulation wool between rafters, carefully filling all nooks and corners


The handling of HDW insulation wool does not entail any health hazards, appart from 'normal' dust (other than glass or rock wool, which contain hazardrous fibre dusts).

One bale fills approximately 0,6 m³ of space. As a guideline: at a density of 40 kg/m³, the spaces will look partially empty. Significant strength is required to reach a density of 70 kg/m³. The wool should always be stuffed without great effort. To guarantee the target density of 50 kg/m³, the required number of bales should be calculated, and all bales should be used.

The bales are transported to the construction area, and if possible are opened and left to relax and rest for one or two days.

Example: Steep roofs insulation with 16cm thickness

roof area 60 m² 80 m² 100 m² 120 m² 160 m² 200 m²
material needed 9,6 m³ 12,8 m³ 16 m³ 19,2 m³ 25,6 m³ 32 m³
number of bales 16 bales 21 bales 27 bales 32 bales 43 bales 53 bales