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Flexible Noise Barrier (FNB) per Meter

  • R 1,200.00
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Flexible Noise Barrier (FNB)

FNB is a flexible, limp, mass loaded vinyl. The product has been independently acoustically tested & certified in a top European lab.

✪ Roll width: 1.37m
✪ Roll length: Typically about 9.1m but this can vary slighty
✪ Thickness: 2.5mm
✪ Minimum order quantity: 1m
✪ We sell per meter

Acoustic rating
STC 26

How Does it Work?

1) FNB adds mass to a lightweight building structure such as a walls, floor & ceilings made from timber e.g. shutterply, OSB, MDF, timber planks, gypsum board, cement fibre boards or any other such boards and even sheet metal. Adding mass to a lightweight building structure is very beneficial in attenuating sound. However not all mass is created equal & this leads me to my second point.

2) The second manner by which FNB works is due to the limp, flexible nature of it's structure which makes it very inefficient at conducting sound, this makes it ideal for soundproofing. A rigid product will conduct resonance more readily than FNB.

3) All structures have an inherent resonant frequency. This becomes problematic when adding further mass of the same type to the structure e.g. simply adding another gypsum board to a drywall. By introducing FNB into the structure the resonant frequency is altered which mean the structure is therefore able to offer soundproofing over a broader frequency band.

FNB converts audible sound energy into inaudible, trace amounts of heat.

FNB is designed to be used inside a structure, to increase the overall sound transmission loss of the structure, for example:


FNB can be used on one side of the stud & track or on both sides of the stud & track for even higher sound isolation.

We frequently use the product to acoustically treat existing drywalls. In this instance, add a layer of FNB to the drywall & then add a layer of 12mm thick Genesis acoustic board, which can then be skimmed, primed & painted to the desired finish. Don't forget to caulk the gaps in the corners closed with Green Glue acoustic sealant. You've only added 15mm to the wall thickness inside the room, which small enough, to never even be noticed. This is a perfect solution for the soundproofing of the drywalls in offices, boardrooms & video conferencing rooms. A single layer of Genesis acoustic board & FNB will provide suitable levels of confidentiality & prevent the details of private conversations being overheard. (It's best to request a member of our team to advise you on all aspects of soundproofing, as sound can take multiple paths)

For installations such as recording studios, post production & home theatre rooms etc. the same approach can be followed on both sides of the drywall, for a broad frequency soundproofing solution.


When installing a new ceiling, first fix a layer of FNB underneath the timber framing with drywall screws or a staple gun, then fix a layer of Genesis acoustic board in place, 12mm is often the thickness of choice (the thicker & heavier the better). Then caulk the gaps in the corners closed, with Green Glue acoustic sealant. Once the sealant is dry, follow with skimming, priming & painting to finish.

When there is already an existing ceiling in place, install a layer of FNB with overlapping joins followed by 1 - 2 layers (50 - 100mm thick) Genesis 60D acoustic insulation, the thicker the better.

Timber Floors

First apply Iso tape to all your beams, screw a layer of 15mm thick Genesis acoustic board to the beams, then loose lay FNB over the floor, followed by another layer of 15mm thick Genesis acoustic board. The same principle will apply if there is already an existing shutterply or pine floor. It's a good idea to cover the floor with Genesis rubber crumb acoustic underlay before laying the final floor finish, this will help to isolate from structural vibration caused by footsteps, movement of furniture etc.

Other applications

FNB can also be used for the soundproofing of many other noise problems e.g. generators, machine housings, the floor of cars, trucks, buses, boats engine compartments, pool pumps etc.


FNB is not sold for its goods looks, it's normally used where it's not seen. It is easily scuffed & being black will quickly show up dirt. However for those unconventional applications when it will be seen, it can be painted, first with an undercoat of universal primer then with a finishing coat of whatever paint is chosen as a finish.


FNB is relatively soft & flexible, it's possible that if insufficient screws or staples are used it could tear due to it's weight, so be sure to use enough. Test a small area first, as what is enough will depend on whether the product is being used vertically, horizontally & the spacing between framing etc. If you use pop-rivets get the ones with the built in washer style head. Use washers for drywall screws. FNB can easily be cut with a sharp blade.

FNB is heavy, it's easier to use it in smaller pieces & butt join or overlap them then to try use very big pieces. It's often wise to work in a team of two people per piece of FNB. Make sure you have a trolly if you'll be carrying rolls onto site.