Durable acoustic panels for ceilings and walls

Troldtekt cement-bonded wood wool panels have the outstanding qualities of the raw materials from which they are made – the robustness and strength of cement and the natural breathability of wood.

Cement-bonded wood wool panels are robust and durable. The setting and curing of the cement adds strength to the panels. The natural properties of the wood make the material breathable and permeable. Troldtekt panels are suitable for screw mounting and are also easy to work with and cut.


The inherent strengths of the panels means that Troldtekt cement-bonded wood wool:

  • has a long service life of at least 75-80 years

  • withstands humid environments such as swimming baths

  • withstands hard ball impacts in sports halls

Long lifespan

Made from a combination of wood and cement, Troldtekt cement-bonded wood wool is a sturdy material with a long product lifespan of at least 75-80 years once the acoustic panels are installed in buildings.

In the Environmental Product Declarations (EPDs), the standard lifespan of cement-bonded wood wool panels is stated as being 50 years, based on generic product information from databases. However, in practice there are plenty of examples of Troldtekt acoustic panels in buildings which are much older.

Several transformation examples

Old Troldtekt ceilings are often preserved when a building is converted and repurposed. One example is ZENI architects’ drawing office, which was one of six nominated projects for the RENOVER Award 2020. The drawing office in Aabenraa is in a former boiler hall, and the original Troldtekt ceilings from 1957 have been preserved. Old Troldtekt acoustic panels can also be painted to create a new look. This was done, for example, in connection with a major refurbishment of Aarhus Airport – rather than going for completely new ceilings.

The impressive durability of Troldtekt acoustic panels has also been evident in connection with the expansion of the company’ s factory in Troldhede in western Jutland. In the process, we bought a number of neighbouring properties dating back to the 1940s, when Troldtekt cement-bonded wood wool was commonly used for plastered wall constructions. In fact, it turned out that the interior walls in one of the buildings concealed 80-year-old Troldtekt panels, which were still in good shape.

Lifespan an important environmental factor

Materials with a long lifespan are good for the environment and for total life cycle costs. A life cycle assessment (LCA) of a building covers the extraction and processing of the raw materials, transport, the production of the various building materials, operation and maintenance, waste treatment and reutilisation.

Often, much of the environmental impact stems from the raw material and production phases, and when a material lasts for 80 years, this impact is spread across a significantly longer period than for a material which is replaced after only 20 years. 

The service period, i.e. the expected lifespan of the building, plays a key role in LCA calculations. The period can vary depending on the building type, and is usually defined in advance if the calculation is performed as part of a certification process.

Leading building certifications such as DGNB, for example, only operate with a 50-year lifespan for buildings. However, as Troldtekt, like several other building materials, has a markedly longer lifespan, it will often make sense to operate with longer service periods, for example of 80-120 years. 

Troldtekt withstands even the most humid rooms

The Danish Technological Institute has documented that Troldtekt acoustic panels are suitable for installing in rooms with:

  • moisture levels of up to 98 per cent (+/- 2 per cent)

  • high temperatures of up to at least 40 degrees.

Troldtekt has thus achieved the highest CE marking level (D) for water resistance.

The documentation shows that Troldtekt is a robust choice for even the most humid and warm rooms such as swimming pools, shower rooms and wellness departments.

The Danish Technological Institute, which is accredited to document the water resistance of materials, has exposed the Troldtekt panels to extremely high levels of humidity. The test was carried out in accordance with the European product standard for suspended ceilings (EN 13964).

To achieve the CE mark’s best class (D) for water-resistance, the acoustic panels must be able to withstand a relative air humidity (RH) in excess of 95% at temperatures above 30°C. 

Troldtekt has been tested to withstand an RH of 98% (+/- 2%) at a temperature of 40°C.

Dimensional stability

Troldtekt panels are dimensionally stable and retain their flatness – which means that they do not warp over time. The Danish Technological Institute has found that the dimensions of the panels only change by 0.005 per cent if the humidity in a room changes by 1 percentage point.

Download moisture stability documentation


Screws and rails protected from corrosion

For installing the acoustic panels in very humid environments where chlorine is also present, Troldtekt offers special structure screws in corrosion protection category C5 (very high). This means, for example, that for suspended ceilings in swimming pools, it is possible to choose a complete C60 profile system in steel, where both the profiles and the screws are C5-rated.

The screws are available in all colours to match painted Troldtekt acoustic panels installed on walls and ceilings.

See range of accessories

Ball impact certification

Troldtekt is ball impact tested in accordance with ‘Prüfung der Ballwurfsicherheit, DIN 18032 Teil 3, Sportshallen für Turnen und Spiele’ (requirements and testing of ball impact safety, DIN 18032, Part 3, sports facilities).

A wide range of constructions with Troldtekt are testet and approved for application as wall and ceiling in sports facilities and gyms where it is exposed to considerable impact when, for example, a handball strikes at high speed.

For further information about test method and certificates, please contact our local distributor

Download overview on Troldtekt's ball impact test certificates

Ceiling and wall cladding in sports facilities and gymnasiums are exposed to stress from ball impacts.

In Germany, documentation is required for the ‘certification to withstand ball impact’ of the materials in accordance with ‘Prüfung der Ballwurfsicherheit, DIN 18032 Teil 3, Sportshallen für Turnen und Spiele’ (requirements and testing of ball impact safety, DIN 18032, Part 3, sports facilities). The tests are carried out at a laboratory in the facility for research and materials testing for the construction industry (Forschungs- und Materialprüfungsanstalt für das Bauwesen (FMPA)) at the Otto-Graf Institute at the University of Stuttgart. The CE standard for suspended ceilings, EN 13964, also includes ball impact certification as a parameter, and the German tests are performed accordingly. In accordance with EN 13964, Annex D, Impact resistance, Troldtekt is classified as class 1A.

A wide range of structures fitted with Troldtekt acoustic panels have been tested at the institute in Stuttgart and have been approved for use as ceiling and wall cladding in sports facilities. This applies to structures on wooden battens as well as structures suspended in C60 profile systems.

Prüfung der Ballwurfsicherheit DIN 18032, Teil 3, Sportshallen für Turnen und Spiele / EN 13964, Annex D, Impact resistance.


Ceiling cladding

A handball is thrown 36 times against the test ceiling at a velocity of 16.5 ± 0.8 m/s. The shots are thrown 2 × 12 times at an angle of 60° and 1 × 12 times at an angle of 90°.


Wall cladding

A handball is thrown 54 times against the test wall at a velocity of 22.5 ± 1.2 m/s. The shots are thrown 2 × 12 times at an angle of 45° and 1 × 30 times at an angle of 90°.

Safety is paramount in indoor shooting ranges

Troldtekt meets the high requirements for indoor shooting ranges in accordance with the German Shooting Range Regulation (Schießstandrichtlinie, SRL) with regard to:

  • the ricochet and rebound behaviour – a projectile energy of up to 7,000 joules

  • preventive fire protection

  • noise protection

35 mm Troldtekt acoustic panels of the ‘Extreme Fine Structure’ type with an intermediate mineral wool/stone wool layer of 40 mm – 50 kg/m3 were tested. Pages 1+26 of the shelling report (VPAM test regulation ARG 2012 version 2 of 14/05/2014) download here or request in full from the relevant Troldtekt project consultant or area manager.

Troldtekt acoustic panels are made of the natural materials of wood and cement and are CE marked in accordance with DIN EN 13168. Troldtekt is classified as a flame-retardant building material (B-s1, d0) and is tested and classified as non-flammable (A2-s1,d0) (download certificates). Troldtekt acoustic panels achieve high sound absorption values over the entire frequency range. (Download sound absorption values).

When planning indoor shooting ranges, special requirements pursuant to the Shooting Range Regulations of the Federal Ministry of the Interior (BMI) (of 23 July 2013, first amendment of 13 March 2013) must be observed in regard to the sound absorption and fire protection. In addition, precautions must be taken against ricocheting and rebounding projectiles or projectile parts when designing indoor shooting ranges.

Sound absorption

Behind the firing line, the walls and ceiling of the shooting range must be covered with sound-absorbing material, depending on the precise use, as residents and other persons must not be affected by the shooting noise (up to 160 dB).

Indoor shooting ranges are facilities in accordance with section 3(5) of the German Federal Immission Control Act (BImSchG) and are subject to the requirements of section 22 of that act. The permissible immission reference values of the Technical Instructions for Protection against Noise (TA Lärm) must be observed.

For the selection of sound-absorbing materials within the shooting range: the mean reverberation time should not exceed the required value of T60 < 0.5 s over the frequency range from 125 to 4000 Hz. The mean sound absorption level should not be less than the required value of αs > 0.5 at the octave average/mean frequency of f = 500 Hz, which is relevant for shooting noise.


Fire protection

It must be ensured that the wall and ceiling materials used do not drip or develop toxic gases in the event of a fire. The sound-absorbing wall and ceiling coverings used in indoor shooting ranges must be at least flame retardant according to building material class B 1 in accordance with DIN 4102, Part 1. According to DIN EN 13501-1, at a minimum the criteria C, s1 and d0 must be met.


Ricochet protection for ceilings and walls

The cladding must be smooth and ricochet-proof. The following safety requirements for the materials to be used must be ensured:

Impacting projectiles must be safely absorbed at a hit angle between 25 degrees and 60 degrees. Projectiles or parts thereof may not ricochet back from the surface towards the shooting positions; the visible material surface must be flat and resistant to abrasion and mechanical stress. Test confirmations or certificates for the resistance of the material used against ricochet and rebound must be available.

Shooting range Gersfeld

After an extensive renovation, the shooting ranges in the German town of Gersfeld have been brought up to date with the latest technology.

Of immense importance are the rebound-proof panels which cover the floors, walls and ceilings of the shooting range. Among other things, Troldtekt acoustic panels were used for this purpose.

The acoustic panels not only optimally insulate the sound and retain the heat in the premises, but they also reflect the light evenly and slow down projectiles to keep them from becoming a danger to the markspeople. 

Read more and see more photos