Ytong blocks

Ytong blocks are flat and block-shaped aerated concrete products manufactured by the Ytong brand (Xella Group), which are used in the construction industry as a solid masonry material for load-bearing and non-load-bearing walls. They consist of autoclaved aerated concrete (AAC) made from natural raw materials: quartz sand, lime, cement, and water. The addition of aluminum powder during the curing process creates a fine pore structure that gives the blocks their characteristic lightness and thermal insulation properties.

Product Variants and Applications

The Ytong range includes various product lines tailored to different requirements. PP2-0.35 to PP4-0.5 flat blocks offer high thermal insulation and are suitable for monolithic exterior walls; they achieve lambda values of 0.07 to 0.09 W/(m·K). PP6-0.60 to PP8-0.80 flat blocks have higher compressive strength and are suitable for load-bearing walls in multi-story construction as well as for interior walls. For lintel and ring beam elements, Ytong offers prefabricated components that are integrated into the flat block system.

Special moisture-resistant variants are used in basements and wet areas. All blocks are laid using thin-bed mortar based on polymer-cement mixtures-mortar consumption is very low due to the minimal joint thickness of 1 to 3 mm, which enables material savings and minimization of thermal bridges. In addition to standard flat blocks, Ytong offers round and arch elements, lintels, wall panels, and prefabricated roof elements for accelerated construction methods.

Installation Advantages and Construction Practice

A key advantage of Ytong blocks in construction practice is their ease of processing: They can be cut to size with a standard hand saw or power saw and planed flat with an aerated concrete planer. Drilling and milling for electrical conduits or anchors is easily possible-an advantage that is particularly relevant for DIY builders and during later renovations.

The blocks’ low weight (8 to 40 kg per block, depending on bulk density) makes them easier to handle on the construction site and reduces the physical strain on the masonry crew. The high dimensional accuracy of the flat blocks results in minimal joints of just 1 to 3 mm, which reduces thermal bridges and lowers mortar consumption. Compared to conventional bricks, which require mortar joints of 10 to 15 mm, heat transfer through the joints in Ytong is negligible.

The following specialized tools are recommended for Ytong masonry: a Ytong hand saw or table saw with a carbide blade, a surface planer for sanding uneven brick layers, a notched trowel for applying thin-bed mortar, and a rubber mallet for alignment. These tools are affordable and widely available; many building supply dealers also rent them out.

Practical Tip for Homeowners in Nuremberg and Franconia

When purchasing an existing building constructed with aerated concrete, it is worth researching the year of construction and the generation of Ytong used. Older blocks from the 1970s and 1980s generally have poorer thermal insulation properties (Lambda 0.12 to 0.16 W/(m·K)) than modern high-insulation blocks (Lambda 0.07 to 0.09 W/(m·K)). An energy performance certificate and a review of the building permit application can provide insight here.

In the Nuremberg metropolitan region, the regional network of Ytong partners in the building materials trade offers a solid foundation for consulting on new construction and renovation. We help you correctly assess the energy performance of an existing Ytong property and make informed arguments during purchase negotiations-whether as a buyer looking to evaluate energy efficiency or as a seller seeking to convincingly highlight the benefits of your Ytong home.

Frequently Asked Questions

Are Ytong blocks really non-combustible?

Yes. Aerated concrete is a purely mineral building material and is classified as building material class A1 (non-combustible) according to DIN 4102. Ytong houses therefore offer significant fire safety advantages over wood-frame constructions or buildings with EPS-insulated facades. Their non-combustible nature also allows them to be used as load-bearing walls without the fire safety restrictions that apply to wood-frame structures starting at a certain building class.

How do Ytong blocks differ from sand-lime bricks?

Sand-lime bricks are heavier and have a higher bulk density (1.2 to 2.0 kg/dm³), which results in better sound insulation values. Ytong blocks are lighter (0.35 to 0.80 kg/dm³) and provide better thermal insulation. For load-bearing exterior walls without an ETICS, Ytong offers an energy efficiency advantage; for partition walls between residential units, sand-lime brick is superior in terms of sound insulation. In practice, Ytong (exterior walls) and sand-lime brick (partition walls) are often combined to optimally meet both requirements.

Can I purchase additional Ytong blocks for a renovation or addition?

Yes, Ytong flat blocks are a standard product and can be purchased through building material suppliers. For renovations and additions to an existing Ytong house, the wall thickness and bulk density class should be matched to the existing structure to avoid thermal bridges and structural discrepancies. Since the Ytong product range has been continuously developed over decades, precise matching of the lambda class is important: Newer high-insulation blocks may require different connection details than the older generations used in the existing structure.

Are there limits to building height with Ytong masonry?

Ytong blocks are suitable for residential buildings up to five full stories (building class 4) as load-bearing masonry-with appropriately sized block densities and structural calculations. For taller buildings, the load-bearing function is typically transferred to other structural systems (reinforced concrete frame, steel structure); Ytong can then still be used for non-load-bearing infill and interior walls. A structural engineer determines the maximum building height and the required block qualities on a case-by-case basis.

How does Ytong masonry perform in terms of moisture protection in building physics?

Aerated concrete has high capillary absorbency and can absorb moisture during prolonged exposure to the elements, which temporarily impairs its thermal insulation properties. For this reason, Ytong exterior walls are typically plastered (exterior plaster on aerated concrete) or clad with a facing shell. Unplastered Ytong is only suitable for interior or weather-protected areas. A proper exterior plaster with a vapor-permeable system plaster reliably protects the wall surface and maintains the thermal insulation properties over the long term. When viewing Ytong homes for sale in the Nuremberg metropolitan area, we recommend carefully inspecting the condition of the exterior plaster-cracks, flaking plaster, or missing foundation waterproofing can indicate moisture problems that will damage the masonry over time.

Sustainability and Energy Performance Certificates for Existing Ytong Buildings

The energy performance certificate is an important indicator when buying or selling a Ytong building in Nuremberg and the metropolitan region. Modern Ytong high-insulation blocks of the current generation (Lambda 0.07-0.08 W/(m·K)) already meet the low-energy or KfW 55 standard without additional exterior insulation when the wall thickness is sufficient (36.5 to 49 cm). Buildings from the 1970s and 1980s constructed with older generations of blocks (Lambda 0.12-0.16) perform significantly worse and benefit considerably from retrofitting with an ETICS insulation system. The KfW development bank and the Bavarian Residential Building Program offer grants for energy-efficient renovation measures, which are also applicable to Ytong buildings.

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