WLS 039 blown-in cellulose insulation
Insulation boards
Plaatisolatiematerialen
Plattendämmstoffe
Mats for thermal insulation
Mattenisolatiematerialen
Mattendämmstoffe
Loose-fill and blow-in insulation materials
Stort- en inblaasisolatiematerialen
Schütt- und Einblasdämmstoffe
Speciality products
Speciale producten
Spezialprodukte
Eigenschaften
As well as their thermal insulation properties, cellulose insulation materials also provide heat protection in summer and have sound-insulating properties. As they are not hydrophobic, they can absorb and release moisture. This ability to store water helps to improve the indoor climate. However, this property means that it is not suitable for cavity wall insulation; it is strongly advised not to use cellulose for cavity wall insulation in double-skin masonry!
There are essentially four methods of application: blowing, inflating, pouring and spraying (cf. cellulose foam). The insulation material is blown into cavities for cavity wall insulation (sloping roofs, timber-frame construction, lightweight interior walls) and in the insulation bag method. Inflation is used, for example, for upper floor slabs, flat roofs and vaults.
Application using the ‘Compact Spray-on method’ (moistening with water mist and, where necessary, the use of adhesive or water glass) differs from traditional blown-in cellulose insulation in that the material can simply be sprayed onto the surface to be insulated and then trimmed to the correct shape. It is therefore suitable for the internal insulation of uneven external walls (rubble stone or half-timbered walls). Once sprayed on and dried, the foam can be plastered over. The main advantages over mat and board insulation materials lie in its flexibility. The cellulose foam can level out uneven surfaces and easily encase electrical cables.
Working with loose material can sometimes generate a lot of dust, which is why protective clothing should be worn during application.
Rohstoffe und Herstellungsverfahren
Raw materials: cellulose (usually from daily newspapers), borates, magnesium salt or ammonium phosphate; for foam: glue is also added
Single-grade waste paper is first pre-shredded in a shredder and then ground in a fine mill into a fibrous, loose material. It is then treated with borates or ammonium phosphates.
An explanatory video
Technical Specifications
Property | Unit | Parameters |
|---|---|---|
Thermal conductivity λB (rated value) | W/(mK) | 0.039 |
| Bulk density ρ | kg/m³ | 25–65* |
| Heat capacity c | J/(kgK) | 2100 |
| Building material class | -- | B2 |
| Water vapour diffusion resistance μ | -- | 1–2 |
| Primary energy content | kWh/m³ | 50–80 |
| Water-repellent properties | -- | no |
*Comparative U-value: 1.0 W/(m²K)
Clean material can be reused. If no borates have been added, the material can be composted. Otherwise, it is sent for thermal recovery, followed by landfill.
ETA-05/0186, ETA-06/0076, ETA 08/0009
Legal provisions:
Blown-in insulation is only considered insulation within the meaning of building regulations if it has been installed by specialist contractors who have been trained in its use by the relevant manufacturer and are included on a list. If installed by a DIY enthusiast themselves, the material will provide insulation but is not legally considered insulation. In the event of damage (e.g. fire), this could lead to problems with insurance companies. Furthermore, any subsidies are not available for buildings in which self-installed blow-in insulation has been used. Even in the case of ‘KfW-x buildings’ or new builds, these insulation materials must not be included in the calculations made by energy consultants or architects.
Gesundheit und Ökologie
From a health perspective, newspaper is a safe raw material. The flame retardant borate, however, is viewed differently if it is used. It has been regarded as toxic to reproduction for some time. The only risk arises from direct inhalation of the substance. Manufacturers do, however, point out that the toxicity of borates is very low, meaning that very high quantities are required before any adverse effects can occur. Borates cannot evaporate, so the consumer has no further contact with the material once it has been installed. For cautious consumers, borate-free products are available on the market.
The use of borates also poses an obstacle from an environmental perspective, as these products are no longer compostable. Borates are classified as slightly hazardous to water (WGK 1). That said, cellulose is rightly considered one of the most environmentally friendly insulation materials thanks to the recycling of waste paper, short transport distances and, overall, low energy consumption during processing.
As a recycled product, very little energy is required to manufacture cellulose. The energy used in production pays for itself – depending on the thickness of the component – between 1,000 and 2,000 times over the course of 50 years.
- extensive experience with this insulation material
- good value for money
- environmentally friendly (low energy consumption during production, short transport distances)
- provides heat protection in summer, sound-insulating
- Additives required (borate, ammonium phosphate)
- only partially compostable (not possible with borates)
- Borates: may be toxic to reproduction