Product presentation Fonofloor B.V.

Acoustic insulation membranes for floating screeds: thin, robust and proven

Since 2002, Fonofloor B.V. has been supplying acoustic insulation membranes to reduce impact sound in floating screeds. "Here we start from the mass-spring-mass principle, in which a 'springy' insulation layer is applied between the structural floor and sand cement or anhydrite screed that absorbs sound waves and vibrations," says Martin van den Bersselaar, Manager at Fonofloor B.V. "Very good acoustic results are achieved with our insulation membranes. The products meet all relevant requirements, including the Building Code."

"Our products are composed of a (largely recycled) bituminous layer and a springy underside of polyester non-woven. The products are delivered in rolls and can easily be rolled out across the floor," Van den Bersselaar says. "All insulation membranes are vapor-tight. If desired, floor heating can be installed on top of the insulation layer. Here we recommend using our Fonofix click rail, which can be glued directly to the insulation layer. This prevents penetrations of the insulation layer - which negate the insulating properties."

Underfloor heating combined with fonofive® applied in a renovation project.

Mineral wool or EPS boards are still regularly used in floating screeds in anno 2019. However, the floor insulation membranes from Fonofloor B.V. have a bituminous top layer, which make the product less vulnerable than traditional products. "Fonofloor^® for example, has very high resistance to dynamic and static loads. You can just walk over it without affecting its function. And water is not a problem either," said Van den Bersselaar. "Fonofloor^® is only 8 mm thick and has a dynamic stiffness of 10 MN/m³. The insulation membrane achieves very good acoustic results, from LnT,A ≤ 49 to well ≤ 39." For renovation projects, which often have limitations in installation heights, he recommends the thinner phonofive^® (6 mm). "Especially for wooden floor structures, we developed fonoblock+^®, a 9 mm thick membrane that combines the extremely high density and acoustic properties of lead foil with a springy layer, making it suitable for both impact sound and air insulation."

Ultimate comfort
Although in the past Fonofloor B.V. mainly carried out new construction projects, for several years the number of renovation and transformation projects has been growing. "For example, late last year we contributed to the transformation of the former headquarters of Verwelius Bouw on Dam Square in Amsterdam into 14 exclusive apartments," says Van den Bersselaar. "In this project, not only state-of-the-art products were used; the performance also had to be guaranteed in advance. With our Fonofloor formula, we can provide this." Whereas the Building Code only has limited requirements for impact noise in renovation projects, this project required a comfort requirement of LnT,A ≤ 49 dB. "Certainly no sinecure, because we were dealing with an old building with thin structural floors, right on Dam Square. Nevertheless, we were able to guarantee an LnT,A ≤ 49 dB with our products in advance, with a joint goal of achieving an LnT,A of 44 dB (ultimate comfort). At the end of last year, the final measurements were taken, which demonstrated this comfort+ requirement."

At an LnT,A ≤ 44 dB, less than 5% of impact noise is still perceived as disturbing, Van den Bersselaar said. "Soon we will introduce a new system on the market that meets this high requirement."

fonoblock+® (9 mm). (Image: photo-eikenburg)

fonofive® (6 mm). (Image: photo-eikenburg)

fonofloor® (8 mm). (Image: photo-eikenburg)

Fonofloor formula
"We have so much confidence in our products that we dare to issue performance guarantees in advance," says Van den Bersselaar. "To achieve these guarantees, we have developed the Fonofloor formula, in which we go through several steps. Starting with the consulting and design phase, in which we like to think along with the architect and structural engineer about the floor construction." Before the application of the insulation membranes begins, Fonofloor B.V. checks the structural floor for imperfections that could negatively affect the insulation value. "Where necessary, we provide tips for improvement, after which our approved preferred processors apply the products. To guarantee that there are no breaks in the insulation layer, we carry out a second round of inspections prior to flowing the anhydrite floor/lubricating the sand-cement floor. With sound measurements, we provide proof of the pre-guaranteed result. The noise measurements are carried out by an independent institute, after which our client receives a performance certificate. With this we not only issue a guarantee on our products, but also on the processing."