insulit Bi+9

The best thin solution 30 dB

The high performance acoustic underlay to limit impact noise transmission

insulit Bi+9 is an acoustic underlay designed to reduce the impact noise between the different floors of a building. With its thin layers, insulit Bi+9 is one of the best impact noise insulation available. This ≥ 9 mm thick underlay achieves better acoustic results than much thicker products, such as acoustic panels or loose-fill insulation materials.

This acoustic underlay is installed on a concrete slab and has to be covered by a min. 6 cm thick screed.

Foam + felt: unique performances!

insulit Bi+9 is made of a reflective and highly resistant aluminised film and a foam+felt double spring structure, maximising its efficiency against impact noise: the felt corrects low frequencies from 100 to 500 Hz and the foam absorbs medium and high frequencies from 500 to 5000 Hz. Supplied as a roll with a self-adhesive overlap, insulit Bi+9 is easily laid onto the floor, with its felt side facing downwards. It can be lifted up against the walls. The ± 10 cm wide lateral foam overlap and its integrated adhesive ensure a clean and neat installation.


  • Outstanding performances
  • Highly tear resistant
  • Thermal confort
  • Included self-adhesive overlaps
  • Very low dynamic stiffness
  • 1.50 m wide rolls
  • Surpasses all standards
  • Quick and safe installation
  • Double structure / double spring effect
  • Efficient at all frequencies
insulit Bi+9 impact noise insulation with heating floor system
  • BBRI
  • VOC
impact noise insulation underlay in roll
impact noise insulation underlay in roll



Aluminised PET film, crosslinked EVA Polyethylene
foam and acoustic polyester felt


≥ 10 mm (under 1,5 kPa)


Metallic (film) / Blue (foam) / White (felt)

Impact noises insulation:

ΔLw = 30 dB (ISO 717-2:2013 ; EN ISO 10140-3:2010)
ΔLw = 34 dB (ISO 717-2:2013 ; EN ISO 10140-3:2010)

Dynamic stiffness:

st = 5 MN/m³ (EN 29052-1)

Tear resistance:

50 – 50 N (EN 12310-1)


≤10 % under 2 kPa (tolerance 10%)

Thermal resistance:

R = 0,30 m²·K/W (EN 12667:2002)

Thermal conductivity:

λ = 0,0356 W/m·K at 10°C (foam) (EN 12667:2001)
λ = 0,0353 W/m·K at 10°C (felt) (EN 12667:2001)


30 m x 1,50 m = 45 m²


±350 g/m² (18 kg per roll)


Included and self-adhesive (± 10 cm)

Datasheet insulit Bi+9 Read online Download