Ytong insulation

Ytong insulation refers to insulation elements and panels made of aerated concrete, which are marketed under the Ytong brand (now part of the Xella Group) and used as a supplementary insulation system for walls, facades, and special applications. Aerated concrete is a mineral-based, non-combustible building material with a porous microstructure that gives it excellent thermal insulation properties-far superior to those of ordinary concrete or brick. As an insulation layer, Ytong aerated concrete complements load-bearing walls and improves the building’s energy efficiency.

Properties and Technical Specifications

Ytong aerated concrete has a thermal conductivity of approximately 0.07 to 0.12 W/(m·K), depending on the bulk density class-significantly better than concrete (approx. 2.1 W/(m·K)), but worse than conventional high-performance insulation materials such as EPS (0.035) or mineral wool (0.035 to 0.045). This generally means that aerated concrete is not used as the sole insulation material, but rather as a complementary building material or one suitable for certain monolithic construction methods.

The particular advantage lies in the combination of load-bearing capacity, thermal insulation, and sound insulation in a single material-especially appealing in the construction of solid single-family homes. Another plus is its vapor permeability: aerated concrete allows water vapor to diffuse, which controlledly dissipates moisture generated during construction and minimizes the risk of mold-an important advantage over closed-cell insulation materials such as PUR or XPS in interior insulation applications.

Due to its low bulk density, the sound insulation values of aerated concrete are lower than those of heavier building materials such as sand-lime brick or concrete. For exterior walls, this is generally sufficient in residential areas (external sound insulation); however, heavier materials are recommended for partition walls between residential units.

Applications: Monolithic Construction and Supplementary Insulation

In monolithic house construction, Ytong blocks with a high bulk density class are used as the sole exterior wall structure, meeting GEG requirements without an additional insulation layer-for wall thicknesses of 36.5 cm or more. This construction method simplifies the building process: it eliminates the need for separate installation of an external thermal insulation composite system (ETICS) or a curtain wall, which reduces the number of tradespeople, coordination efforts, and potential sources of error.

As supplementary insulation, Ytong insulation boards are installed on existing exterior walls to improve the energy efficiency of existing buildings. Advantages over other insulation systems: a fully mineral-based construction with no fire risk, good workability with saws and planes, and vapor permeability that minimizes moisture problems in the structure. For building owners who do not wish to use synthetic insulation materials for fire safety reasons or personal convictions, aerated concrete is an attractive alternative.

Environmental Aspects and Sustainability

Aerated concrete is made from natural raw materials (quartz sand, lime, cement, water). The manufacturing process is energy-intensive, as steam curing in an autoclave is required. However, aerated concrete is fully recyclable: broken material can be reused as aggregate in the construction industry, and some manufacturers offer take-back programs.

Compared to EPS or PUR insulation materials, aerated concrete is considered more environmentally friendly-no synthetic polymers, no blowing agents with global warming potential, and no pollutants during disposal. The gray energy consumption (primary energy required for production) is higher than that of mineral wool or EPS, but this is offset by the material’s long service life and its combined load-bearing and insulating properties.

Practical Tip for Homeowners in Nuremberg and Franconia

In new construction projects in Franconia, aerated concrete is a popular alternative to brick or sand-lime brick-especially among DIY builders and homeowners with hands-on skills, who appreciate how easy the material is to work with. Anyone wishing to renovate an existing building with aerated concrete insulation panels should have an energy consultant verify compatibility with the existing substrate and compliance with GEG requirements in advance.

In Nuremberg and the surrounding Franconian region, regional building material dealers and manufacturers offer consulting services to assist with product selection. We help you accurately assess the energy performance of your property and communicate this transparently in your marketing-including in the energy performance certificate, which often accurately reflects the actual thermal quality of Ytong buildings when it is issued based on the building’s energy demand (demand certificate).

Frequently Asked Questions

Can Ytong aerated concrete be used as the sole exterior wall insulation without an external thermal insulation composite system (ETICS)?

Yes, with sufficient wall thickness (36.5 cm or more for flat blocks in the Lambda class 0.07-0.09 W/(m·K)), Ytong can meet the GEG requirements as a monolithic exterior wall without an additional ETICS. For passive house standards, additional insulation layers are generally required, as the monolithic Ytong wall alone does not achieve a U-value below 0.15 W/(m²·K). A combination of a Ytong load-bearing wall and a thin external thermal insulation composite system is cost-effective in this case.

Is a Ytong wall moisture-resistant?

Aerated concrete is porous and can absorb water. Persistently damp conditions-such as areas in contact with the ground or unprotected exterior walls without plaster-impair the insulation properties and load-bearing capacity. Exterior plaster or cladding is absolutely necessary. In areas exposed to splash water (base zone) and for components in contact with the ground, more moisture-resistant building materials such as sand-lime brick or XPS-insulated concrete are preferable. Ytong manufacturers offer special moisture-resistant flat blocks for the base area.

Are renovations using Ytong insulation panels eligible for government subsidies?

Yes, provided the minimum technical requirements of the Federal Subsidy for Efficient Buildings (BEG) are met and an energy consultant oversees the project. Mineral insulation systems are generally eligible for subsidies; compliance with the required minimum R-value must be demonstrated. Since aerated concrete insulation panels require comparatively thick wall structures to achieve the required thermal resistance, careful advance planning is essential.

How do Ytong insulation panels perform compared to mineral wool and EPS in the event of a fire?

Ytong aerated concrete is non-combustible (building material class A1 according to DIN 4102), whereas EPS and PUR can be made flame-retardant but are not completely non-combustible. In the event of a fire, a Ytong facade protects the building better than an EPS ETICS because there is no organic material present that contributes to the fire load. Mineral wool is also non-combustible, but offers no load-bearing capacity. This property makes Ytong particularly attractive for buildings with increased fire safety requirements-such as multi-family homes with four or more full stories.

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