ONE-BLOCK: a Highly Acoustically Insulating Party Wall

Actualité | SWISS KRONO Germany

When specialists for acoustic insulation and engineered wood materials team up, great products result. Together with Wolf Bavaria, we came up with the idea of creating an extremely thin wall that is made completely of wood-derived materials and provides excellent acoustic insulation (R_W > 60 dB). The idea was that it would eliminate the need to add soundproofing at the construction site. The wish list also included good stackability and easy installation using only screws. Sustainability and eco-friendliness were a matter of course.

And the result? A party wall for separating adjoining flats which we have dubbed ONE-BLOCK. It’s a dismantlable, acoustically insulating exposed wall with a bendable, free-floating core that attenuates sound levels by 66 dB despite being only 265 mm thick, thus exceeding our target by ten percent. The ONE-BLOCK wall is structured as follows:

• 125 mm of MAGNUMBOARD® OSB (on the source room side)
• 25 mm of PhoneStar Schalli acoustic insulation and decoupling strip
  • with 20 mm of mineral wool
• 15 mm of PhoneStar Tri acoustic insulation
• 25 mm of PhoneStar Schalli acoustic insulation and decoupling strip
  • with 20 mm of mineral wool
• 75 mm of MAGNUMBOARD® OSB (on the receiver room side)

Tests by IFT Rosenheim have shown that PhoneStar, when installed centred and flanked by tuned mass dampers (TMDs) on both sides, attenuates airborne sound by an additional 14 dB. The screws inserted during transport reduce the acoustic insulating performance of the overall assembly, but as soon as they are removed airborne sound is dampened by an impressive 66 kB.

MAGNUMBOARD® OSB excellently meets the structural and loadbearing requirements. The wall’s thickness can be flexibly adjusted depending on the required level of fire protection. Another benefit of using MAGNUMBOARD® OSB is the possibility of direct finishing: plaster, tiles, paint or wallpaper can be directly applied to the OSB surface without requiring an intermediate layer of another material. PhoneStar Schalli (link available in German only) is a multilayer sound insulation and decoupling strip containing loose sand that very effectively reduces sound transmission, and PhoneStar Tri (also only available in German) is a highly acoustically insulating, heavy yet flexible plate that also comprises multiple layers and loose sand for enhanced sound attenuation.  Together with the air gap, Wolf MiWo mineral wool (link available in German only) acts as a bendable, freely oscillating spring that amplifies the sound-attenuating effect of the PhoneStar Tri board.

Benefits of the ONE-BLOCK party wall at a glance:

• No spring rail or acoustic isolation clip required
• Consists of a single block
• Can be prefabricated
• Significantly reduces airborne sound

These PhoneStar products meet all of the relevant sustainability requirements for qualifying for KfW subsidies. SWISS KRONO OSB/4, the material used to produce MAGNUMBOARD® OSB, also fulfils the criteria for the German federal government’s QNG quality seal for sustainable building. Boasting an environmental product declaration (EPD), the German Blue Angel ecolabel and PEFC certification, SWISS KRONO MAGNUMBOARD® OSB is the ideal engineered wood material for making this solid party wall.

This double-leaf party wall will soon be added to the SWISS KRONO PLANNING TOOL under numbers B9399 and B9402. You can also find many other wall and ceiling modules there that have been developed and tested in cooperation with Wolf Bavaria.