MHM Walls

Here is all the comprehensive information about the characteristics of MHM walls. If you need more technical data, download our additional documents and certificates.

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Thermal insulation of a house has many more benefits than just reducing heat loss. It also means lower energy consumption for heating, increased comfort in using the interior, enhanced fire safety, improved acoustic comfort, and extended house structure lifespan.

Insulation also serves a cooling function, especially during the summer months. The concept of insulation complements the overall exterior aesthetics of the house, and ultimately, insulating the house increases its value.

Important considerations for

Achieving a sufficiently low U-value is essential to prevent heat loss in winter and comply with relevant building regulations. At the same time, attention must be paid to creating exterior cladding with adequate heat storage capacity so that its slow reaction to temperature fluctuations can counteract excessive heat on hot summer days.

  • Thermal inertia: specific heat capacity, cp, according to EN ISO 10456 up to 1600
  • Thermal conductivity of walls: λD = 0.11 W / (m * K)
  • Thermal conductivity of ceilings: λD = 0.13 W / (m * K)

From January 1, 2016, the design of external walls must meet the standardized value of thermal resistance R = 4.4 m2K/W (U = 0.22 W/(m2.K)).

From January 1, 2021, it is recommended to design all new buildings and renovated buildings to a target thermal resistance of R = 6.5 m2K/W (U = 0.15 W/(m2.K)) for external walls.

An ideal solution is a ventilated wooden façade.
To maintain the walls' diffusion properties, wood fiberboards or mineral wool must be used, as well as a render that allows water vapor to pass through


Mechanical vibrations that propagate through flexible media due to the vibrations of material particles around their equilibrium position, causing densification and dilution of the media.

Airborne sound

Sound that propagates through the air, such as music from a radio.

Structure-borne sound

Sound that propagates in solid materials, such as from a percussion drill

Footstep sound

Sound generated by walking, including on ceilings and stairs, in the form of structure-borne sound, which partially penetrates into adjacent rooms in the form of airborne sound.

Acoustic insulation is an important criterion for the quality of residential and working spaces in buildings.


Acoustic insulation is an important criterion for the quality of residential and working spaces in buildings. Standard STN 73 0532 regulates minimal building requirements.

In the case of family homes, versions with effective sound insulation should always be chosen, as legal requirements here apply not only to the standard but also to generally accepted principles of construction technology.

When planning larger projects, such as family homes or public buildings, the sound insulation specified by the standard is always ensured. Careful planning is necessary to achieve the required or agreed-upon sound insulation values. This, of course, also applies to walls in the Massiv-Holz-Mauer® system.

  • MHM walls are tested for airborne sound insulation according to the European Technical Assessment ETA 15/0760, dated 30.06.2017.
  • All contact points with connections between walls and ceilings are isolated with sound-insulating tapes.
  • Floors with sound absorbers around walls should be used and placed on a sound-insulating layer.
  • Connectors with acoustic pads can be used on the wall or ceiling to increase acoustic insulation by reducing acoustic bridges.
  • To enhance acoustic insulation, lightweight panels filled with mineral wool according to the chosen system can be installed before the wall or ceiling.
  • Sound pads based on the elastomer system can be introduced in buildings with exceptionally high acoustic requirements.
  • Leaving the ceiling exposed, the edge system of the panels significantly improves acoustics and reduces the effect of reflection.

MASSIV-HOLZ-MAUER® has a fire protection classification of REI 90 (F90 B).

While other building materials commonly used in the industry are usually classified only in terms of fire protection REI 30 (F30).

The wood in the MASSIV-HOLZ-MAUER® wall contains up to 15% water, which must first evaporate in case of fire (150 liters of water per ton of wood). When it burns, the upper layer turns into wooden charcoal, which, due to its extreme porosity, acts as an insulating layer and does not allow hot air to pass through to the deeper layers of the MHM wall. Oxygen can no longer penetrate the wood, and its combustion is significantly slowed down. Due to the low thermal conductivity of wood, the risk of self-ignition is also very low.


REI 90 for walls with a thickness of 20.5 cm or thicker, with one-sided cladding with 18 mm plasterboard - classification report no. KB 3.2 / 14-013-3 issued by the German certification body MFPA Leipzig GmbH on 30.06.2015.

Fire reaction - European class D-s2, dO.

  • open diffusion, reducing water vapor from the inside (diffusion resistance value μ = approximately 65)
  • regulates humidity inside the building

According to temperature and humidity calculations, thermal insulation should be used to prevent the formation of dew points inside the wall. Calculations according to EN ISO 13788 show that for an apartment building with a perimeter wall thickness of 20.5 cm, 10 cm of wool with λ = 0.039 W / (m * K) is sufficient.

Building insulation is applied in the same way as masonry technologies. As in any modern building, walls susceptible to moisture should be protected from humidity (for example, using liquid waterproofing).

The tightness of joints and the quality of the mutual contact of elements play a decisive role in achieving tightness. To ensure the normative wind resistance, which every supplier is obliged to adhere to according to the European technical approval, we apply the following:

  • A high-quality wind-resistant membrane manufactured by companies such as Rothoblass, Siga, and others ensures the connection of walls and ceilings from the outside of the building and from the sides of all openings of external walls.
  • The tightness of the joints is ensured by expansion material.
  • All joints are sealed with flexible tape.

If it is necessary to ensure a tightness of n50 <0.6 1/h for a passive building, the entire surface of the external partitions should be covered with wind insulation, which is sealed at the joints in accordance with the chosen wind insulation system. Such a construction is tested with a so-called blower test.


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