Environmental awareness and the need to build energy efficient give a new impulse to Wood Wool Cement (WWC) building products. In recent years the Swedish WWCB producer Träullit (www.traullit.se) developed a revolutionary new building system with high thermal insulation, consisting of large homogeneous WWC Wall Elements of up to 6 m length and 260 cm height. The thickness of the WWC elements is up to 40 cm.
The main properties of this unique new building system are:
- Energy efficient (incl. Passive Housing)
- Excellent thermal insulation
- Damp-open construction resulting in good moisture balancing properties and excellent living conditions
- Fast modular construction
- Exceptional sound absorption
- Fire resistant (6 hour fire-rating achieved)
- Termite, mold/fungi and vermin resistance
- Good mold/fungus resistance
- Excellent workability
- Simple ingredients: (industrial) wood, water and cement
- Low specific weight, resulting in reduced transport costs
Due to high thermal insulation values, superior thermal storage capacity and moisture balancing properties, this system is ideal for residential construction, especially for countries with a cold climate such as in Northern regions. In countries with land climates and warmer to hot climates the same properties help to significantly reduce energy cost for cooling. In all cases the high insulating value is appreciated for maintaining a comfortable indoor climate and excellent living condition
Not only the Thermal Insulation value but also the Thermal Storage Capacity is important, as shown below.
| Comparison of Thermal Insulation and Storage Capacity of various Wall constructions (source Träullit) | Thermal Insulation W/m² ºC (U-value) | Thermal Storage Capacities KJ/m² °C |
|---|---|---|
| Wood Framed Mineral Wool | 0.14 | 65 |
| Large WWC Wall Element | 0.19 (R=5,26) | 250 |
| Light Weight Concrete | 0.28 | 210 |
| Expanded Clay Blocks (Leca) | 0.50 | 255 |
The Large WWC Wall Element Building System
After the Wall Elements are manufactured in the factory, they are loaded on a truck and shipped to the job site. There, they are installed on the prepared foundation in only one day. First, the Wall Elements are connected by pouring fresh concrete in prepared reinforced vertical cavities where the Elements join. As a second step a reinforced concrete ring beam is poured in a prepared groove on the top of the Elements. Finally, after all concrete is cured, the roof is installed. Optionally, also the roof is constructed using the highly-insulating Träullit wood beam-reinforced WWC Roofing Boards.
As a finish the Elements are provided with window-frames and a stucco/plaster. These operations can either be performed in the in the plant or optionally be done at the building site.
