Dimensioning for good acoustics is crucial when working with wooden structures, where floor joists often constitute a weak point for sound transmission. Granab has over 30 years of experience in developing subfloor systems with high sound performance, especially for wood-based joists such as cross-laminated timber (CLT).

Granab’s System 8000W, with Sylodyn damping material measuring 6/12/25 mm and dimensionally stable wooden beams, is specially designed for CLT floor structures. The system enables:

• Effective damping of impact sound, documented by laboratory and field measurements and type approval with improved sound insulation even at low frequencies (from approximately 50 Hz and above). Results may vary depending on the entire floor structure and installation.
• Reduced airborne sound, where the system’s type approval and measurement results show that it can contribute to achieving sound class A – according to Swedish standard SS 25267. This is provided that other building components also meet the requirements. The sound classes depend on the entire building’s construction.
• Adaptable dampening, where different Sylodyn variants (ND, NE, NF) and thicknesses are selected based on load requirements from approximately 300 to 1000 kg/m² to optimise sound damping and adapt the system to specific building requirements.

In projects involving CLT flooring, it is common to use 25 mm Sylodyn to meet acoustic requirements – a solution that has been used in examples such as Sävja Trähuset, Ås School, Brf Gourmet and the Tempelriddarorden nursing home.

Granab works closely with acoustic consultants and offers detailed calculations, including natural frequency analyses and field measurements. The system is type-approved by RISE, which means that the sound insulation has been rigorously tested in laboratory environments.

Sylodyn material is recyclable, age-resistant and environmentally friendly – part of the system’s overall sustainability promise.