Sound-transparent, jointless lamination of acoustic ceilings made of perforated plasterboard with DEKOZELL® acoustic spray filler

Please adhere strictly to the instructions described on the following pages during application–otherwise errors are virtually inevitable.

The application of the system is basically quite simple. The potential for errors is often hidden in the details!

Possible sources of error



Substrate not Q2.

Risk of marking of substrate unevenness.

Not primed with DEKOZELL Isogrund.

No clearly defined absorbency and adhesion of the substrate, therefore risk of delamination. The Isogrund protects the plasterboard during the drying time of the spray filler and also prevents the screw heads from rusting during the drying phase.

Adhesive bed thinner than 300g/m².

No full-surface adhesion of the acoustic plaster base fleece, therefore risk of detachment or voids.

Acoustic plaster base fleece not bonded with DEKOZELL dispersion adhesive.

Risk of detachment during drying of the final coating due to insufficient water resistance of the adhesive bond.

Acoustic fleece not pressed down with wallpapering spatula after application.

No full-surface adhesion of the acoustic plaster base fleece, therefore risk of detachment.

Adhesive dried before laying the next track.

Danger of marking out of steps, the final coating with acoustic spray filler only compensates slightly.

Acoustic spray filler applied too thinly or to very different thicknesses.

Risk of holes in the GK board showing through after sanding. As a remedy, a second coat is necessary.

No polishing sanding with eccentric and 320 grit, only basic sanding with Flex Giraffe.

Sanding marks, sanding grooves and uneven velvet sheen as a result of not polishing.

Screws not filled and not sealed with Isogrund.

Formation of rust stains during drying. Remedy only possible by partially replacing the top coat.

This list of errors does not claim to be complete (completeness on website). We generally recommend that inexperienced tradesmen set up a practice area or book a construction site training course. These instructions do not release you from the instructions in our technical data sheets!





Install perforated panels according to the manufacturer’s instructions and fill/sand to Q2.

Install perforated plasterboard ceiling according to manufacturer’s specifications Knauf or Rigips and pre-fill/sand to Q2 and prime with deep primer all around at least the ceiling edge. In principle, any perforation can be laminated, but the use of maximum perforation 12/25 is generally recommended from an acoustic point of view.

Do not forget to place a mineral fiber mat as the actual sound absorber behind the perforated panel!

Overlap the adhesive tapes
so as not to tear away the dried Isogrund or dried adhesive at the very end and thus damage the still wet edge of the acoustic spray trowel.

The final coating with the acoustic spray filler applies a layer thickness of approx. 5-6 mm when wet, which then shrinks to approx. 3 mm during drying. It has proven to be a good idea to apply a fabric adhesive tape (e.g. Tesa 4363, width 35 mm) approx. 5 mm below the ceiling before applying the insulating primer. The blue fabric tape will later form the final edge of the acoustic spray filler. So place this tape neatly!

The masking film for the wall can also be clamped under the blue fabric tape (e.g. masking film purple no. Secure).

To ensure that the Isogrund and then the dispersion adhesive do not adversely bond with the blue fabric tape, we recommend overlapping this blue tape by a few millimeters with a weaker adhesive crepe tape or yellow grooved PVC tape:

  • once with masking tape for the isogrund (remove immediately after application!)
  • After the Isogrund, apply another new masking tape for the adhesive of the acoustic plaster base fleece (remove again immediately after application!)

The blue fabric tape is then removed after smoothing the acoustic spray filler.

It is best to protect the entire surface of the floor with 0.1 mm construction foil and then again with painter’s fleece because of the risk of slipping due to the long open time of the acoustic spray filler.

 Avoid ‚snotty noses‘!
Uniform, rich isogrund layer.
Use the scraper grid!

Apply DEKOZELL Isogrund (Profitec P564) primer to a surface quality Q2.

The substrate must be free of thermal bridges and at least as warm as the ambient air to avoid condensation.

Apply Isogrund to cover the entire surface. Avoid the formation of “snot noses”, as these hinder the bonding of the acoustic plaster base fleece in the next work step. If in doubt, apply two thin coats of primer rather than one thick coat.

Do NOT mix quartz sand into Isogrund!

Use a wiper grid, otherwise the “snotty noses” are automatically pre-programmed!

Dry Isogrund at at least 15°C for at least 12 hours.

If the temperature is insufficient, the Iosgrund dries but does not develop any insulating effect and therefore remains useless!

Apply DEKOZELL® dispersion adhesive
Attach and align the fleece. Roll 1x50m.
Carefully press down 40 cm of fleece with a surface spatula to avoid cavities.
Press on the fleece in the Ixel with a spatula and cut off. Apply plenty of adhesive to the edge!

Pour the DEKOZELL® dispersion adhesive from the 5 kg container into an empty paint bucket and apply undiluted with a roller. Use approx. 300-400g adhesive per square meter. Slight “snotty noses” are permitted in this step, but if too much adhesive is used, the plaster base fleece will run into the holes so that sound can no longer pass through the holes and the acoustic effect is lost.

We strongly recommend the use of DEKOZELL dispersion adhesive, as this also provides the necessary water resistance. The acoustic spray filler remains wet on this adhesive bond for several days during the drying time!

It is highly recommended that the glass fiber fleece is only handled with protective gloves. Small, fine glass needles trickle out, especially when pressing down – appropriate respiratory protection and safety goggles are therefore highly recommended.


Clean the pressure spatula from time to time with a damp cloth.

Apply extra glue in the Ixel. The last row of holes is usually filled anyway.

Don’t forget to remove the second piece of masking tape from the edge as soon as possible.

Overlap two rows for a double cut.
Make the cut so that the bottom strip is wider rather than too narrow.
Remove the bottom strip.
Carefully press down 40 cm of fleece with a trowel to avoid voids.

The fleece is usually laid in a double cut, alternatively butt laying would also be possible.

For double-cut fleece, allow two rows of holes to overlap the previous strip and roll these two rows of holes in with adhesive.

The bottom strip is easier to remove when double-cutting if it is at least one row of holes wide, as a very narrow strip will tear more quickly when removed.


Apply a little glue to the cut edge (but don’t fill all the holes with it straight away!)–this prevents the risk of cavities.

Drying phase of the dispersion adhesive

After laying the acoustic plaster base fleece, the dispersion adhesive must dry out completely before proceeding with the final coat of DEKOZELL Acoustic Spray Filler.

At 22°C air and substrate temperature and max. 65% humidity, 12 hours are usually sufficient for the adhesive to dry. Thermal bridges hinder drying and can even lead to delamination.

Mix DEKOZELL® acoustic spray filler and fill the STORCH plaster gun with it. Nozzle 4mm or 7mm.
Alternatively, prepare the Inomat M8 spraying machine as an alternative to the gun, which requires a little more set-up time, in accordance with the “Processing with the Inomat M8” instructions.

Mix DEKOZELL® acoustic spray filler with 15 l water and 1 l DEKOZELL® dispersion binder without lumps – approx. 3 minutes stirring time per bag.

Equip STORCH plastering gun with conical 4mm nozzle made of 4-hole disk and pre-rinse with water before filling. After filling with acoustic spray filler, press the gun firmly onto the floor with the gun handle.

As an alternative to the STORCH cleaning gun, the Inomat M8 spraying machine with DEKOZELL fine spraying set can also be used. Although working with the machine is somewhat easier than with the spray gun, there is no great advantage in terms of time. The main advantage of the machine with the spray filler is the more relaxed working from the ground and the resulting more even material application. The more evenly the spray filler lies, the easier it is to smooth and the lower the risk of sanding through.

Rise to working height with the filled gun and apply the acoustic spray filler in even circular movements. The handle of the STORCH spray gun can be placed on the shoulder to relieve the strain.

Apply one bag of acoustic spray filler (approx. 20 l ready-mix) evenly to a maximum of 8 m². Spray extra thick in the corners and on the edges, as filler will be removed from there when smoothing. After drying, spray another 8 m² with one bag – for a total consumption of 4 m² per bag.

When spraying with a gun, we recommend using a small roller scaffold or at least a plank. When working on larger areas, the machine is easier to handle. Here too, divide the material consumption strictly according to the area: apply one bag to a maximum of 8 sqm/4 sqm – otherwise the layer thickness will be too thin afterwards when sanding.

The long open time of the DEKOZELL® acoustic spray filler means that an unusually long time is available for smoothing. The spray filler remains soft and smooth throughout the entire working day! This means that a single person can do an entire ceiling on their own (without expensive surface scaffolding!). When applying with a gun, the spray filler can first be leveled with the smoothing blade, then switched to the Pajarito plastic filler item no. 958. When spraying with the machine, with a little practice the material will lie so evenly from the outset that you can use the red plastic trowel straight away.

Then apply the red plastic trowel to the edges on the blue adhesive tape first and pull the filler up from there onto the ceiling. First smooth the edges, then the surface. During drying, the spray filler shrinks by approx. 50%–slight trowel strokes from the application of the smoothing tool are therefore significantly equalized during drying. Pull the red plastic trowel completely flat and without pressure over the surface – without circular movements and without holding the trowel steeper at the end of the stretch: Always start flat with the arm extended, pull the arm straight through to the body at this angle without applying pressure until the lower arm is vertical – and then simply remove the trowel from the ceiling at exactly this angle without bending the tool again! When “edging”, you would only push the soft spray filler away, just as with the usual circular movements of the arm when filling. After initial skepticism, many craftsmen describe smoothing with the acoustic spray filler as ‘totally different, but much easier’.

After smoothing, remove the blue adhesive tape and tidy up the construction site. There are now almost 4 liters of water per square meter of acoustic surface in the room! To evaporate water, heat is required, at least 20°C – preferably 22°C or even more. We generally recommend the use of fans from the outset. Shock ventilation is not enough, ventilation must be continuous! The use of condensation dehumidifiers in conjunction with fans is better than fans + ventilation. The dehumidifiers must have sufficient capacity! We recommend a theoretical dryer capacity of 3 liters per square meter of acoustic surface (e.g. a 120 liter dryer for 40 square meters of acoustic surface).

The acoustic spray filler must dry completely within 3-4 days!

If this drying time is exceeded, problems such as mildew stains are to be expected.

Basic grinding with Flex Giraffe
Polishing with the 900g lightweight DEROS and Abranet 320 grit.

After drying, sanding is carried out in two stages: first the basic sanding with the Flex Giraffe, then another short polish with the Mirka CEROS 650CV eccentric.

The Giraffe can be used with any abrasive grit down to 40 grit. However, polishing with the Mirka eccentric must be completed with Abranet in 320 grit.

Sanding is also carried out with the giraffe from a working height so that you can see what you are sanding! With the long-necked giraffe, you can also rest the device on your shoulder.

Insert a bag in the vacuum cleaner – for both the giraffe and the eccentric. The vacuum cleaner’s knock-off device does not work with cellulose dust.

The DEROS 650CV works practically dust-free thanks to the 48 suction holes in the plate. Polishing takes perhaps one minute and is also used later for renovation.

Error pattern: this is what it looks like when the spray filler is sanded through on the perforated plate. The small pores are air pockets that occur when there is too much air in the spray pattern. Nevertheless, finish sanding the surface here first – and then recoat again.

These sanding marks here come from the giraffe, the eccentric just takes them away. After polishing, the surface is finished. A coat of paint with a roller would block the sound permeability of the acoustic spray filler and destroy all the work!


We give everything for your smooth result.

Seamless acoustic plaster systems are still a niche product. But one that we live and love. We have specialized in it, are really good at it and do it with enthusiasm. And we offer you and your team the expertise, performance and flexibility you need to get the job done. For both small and large projects.

Vivian Neubauer
Vivian Neubauer
Dipl.-Ing. Printing Technology
Thomas Neubauer
Thomas Neubauer
Dipl.-Ing. Process Engineering, Master of Business Administration

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„As experts for good sound in a room, a pleasant, natural acoustic atmosphere is essential for us. We advise our customers holistically, with the most suitable absorber solutions for the room and customer. Whether using our invisible loudspeakers SONUS INTARA, which can also be easily accessed again, or the impressive 5,000 square meters of wall and ceiling in the Kunst-Museum Reinhardt Ernst. If you want seamless invisibility, we can warmly recommend DEKOZELL.“

Joachim Kistner, Managing Director
SONUS Acoustic Solutions, Baden-Baden

„We develop tools for creative people to optimize spaces such as recording studio control rooms, recording rooms or concert halls. In 2012, we were looking for a seamless acoustic plaster solution for the redesign of control room 7 at ORF Vienna. All of the competing systems could not be repaired and the trickling onto the expensive sound technology was also unacceptable. With DEKOZELL, we have had a capable acoustic plaster partner ever since.“

Peter Willensdorfer, Managing Director
tonarchitektur Willensdorfer, Vienna

„We build atmosphere for our discerning customers. Mainly for high-quality residential buildings. We strive for an aesthetic that emphasizes simplicity. Rough and sensitive acoustic plaster ceilings have always caused us problems. DEKOZELL, on the other hand, is simple, beautiful and smooth. And gives us a new freedom in design.“

Georg Weber, Architect
Hillekamp & Weber Architecture Studio, Mönchengladbach

„We have already worked with almost all acoustic plaster manufacturers. DEKOZELL was a game changer for us. Absolutely invisible repairs and the very special feel of the surface convinced us completely. Today, we have more than 30 people working on the acoustic spray filler and use several spraying machines.“

Jörg Held, Managing Director
Steuernagel & Lampert, Painting company, Groß-Bieberau

„Acoustic plaster is a top priority for me. Because DEKOZELL acoustic plaster systems are usually included in the painting tender, I have already received several villa projects as a complete order. Sanding really does the trick. Difficult installation situations or quick repairs are no problem. I also really like the DEKOZELL sealant for the edge connection, which looks exactly right.“

Peter Rumohr, Master Painter
Malerwerkstätte Rumohr, Krefeld

„We create color concepts and develop extraordinary surfaces with sensitivity and aesthetics surfaces that emphasize uniqueness. Room acoustics are a central theme here. In DEKOZELL, we have found a partner with whom we can meet the high demands of our customers.“

Harald Jehle, Master of Colors
polychrom Jehle, Weingarten

„We have been processing DEKOZELL for many years now. As a two-man business, we can therefore get involved in what is an extremely interesting and lucrative market for us.“

Hermann Kilgus, Master Painter
Kilgus Painting and Varnishing company, Leutkirch

„I was highly skeptical at the beginning. Our customer wanted FLEXOPANEL on the ceiling and on a large wall. We’d never done that before. Through WhatsApp video calls and top work instructions, we grew into it step by step. We are delighted with the result. And so was the customer.“

Enes Zhegerova, Fabricator
Dietrich Plasterer & Color Design, Wüstenrot

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