We want to build, is what is being offered to us okay?

So I have 17.5cm stones for non-load-bearing interior walls.... I would just have a weird feeling about such thin exterior walls, going by gut feeling. The insulation might be okay, but if I'm building solidly, then really solidly. But that's just my amateur personal opinion on it. Alex

Hm, but okay. It is already a valuable statement for me that the static structure is what prompts it and not primarily the insulation or anything else.

That always depends on the wall. A aerated concrete block also insulates (at the expense of thermal storage capacity and sound insulation) and must simultaneously bear loads. In the case of a double-shell masonry, it makes sense to separate the structural load and the insulation (but of course, this is not mandatory). Simply put: the heavier, the worse the insulation but the better the soundproofing and thermal storage capacity; the lighter, the better the insulation, the worse the soundproofing and thermal storage capacity. Aerated concrete weighs about 400 kg/m³, a perforated brick around 700 kg/m³, calcium silicate brick up to 2200 kg/m³ – these values are just guidelines, because there are about 100 different types of bricks (more or fewer holes, etc.).
A matter of belief – there are people who swear they can hear their neighbors on the terrace through the aerated concrete wall, there are people who avoid aerated concrete because of the aluminum, others swear by natural brick and curse mineral wool, yet others say only a monolithic house is a real house... etc. pp. Only on one thing are they all agreed: PU stinks.

That always depends on the wall. A aerated concrete block also provides insulation....

**Aerated concrete

It is a highly thermal insulating solid building material that, due to its closed-cell pore structure, can take on both static and building-physics properties – usually without additional measures and complementary materials. It is made from local raw materials and has the almost unlimited lifespan typical of solid building materials.

Thermal insulation:

Aerated concrete is the only solid building material with a thermal conductivity starting at 0.09 W/(mK) in the density classes 0.30, 0.35, and 0.40. This means: A single-layer 30 cm thick wall already offers a heat transfer coefficient U = 0.28 W/(m2K). With a wall thickness of 36.5 cm, the U-value drops to 0.23.
In the exterior wall area, the requirements of the Energy Saving Ordinance (Energieeinsparverordnung) can therefore be met and even exceeded without additional insulation measures. Moreover, the homogeneous wall construction allows for nearly thermal-bridge-free designs. A plastered single-layer wall made of aerated concrete is considered airtight within the meaning of the Energy Saving Ordinance without additional measures.

Heat storage:

The heat storage capacity of aerated concrete lies between the extremes of lightweight construction (e.g., timber frame construction with approx. 50 kJ/m²K) and solid construction (e.g., masonry or reinforced concrete with approx. 250 kJ/m²K). The corresponding value for an aerated concrete wall is approx. 90 kJ/m²K.

Thermal conductivity:

Due to the very low thermal conductivity of 0.09 W/(mK), the requirements of the Energy Saving Ordinance can be met with aerated concrete in monolithic construction. A multilayer structure in the case of an exterior wall, as usual with other building materials, is unnecessary.

Diffusion resistance:

Due to the porous structure, the water vapor diffusion resistance factor of aerated concrete is low and ranges between values of µ = 5 to µ = 10.

Sound insulation:

Aerated concrete relativizes the physical principle “The heavier a component, the better the airborne sound insulation.” Because, due to its pore structure, aerated concrete has an internal damping effect of sorts. Also, DIN 4109 takes this into account: Aerated concrete walls with a surface weight up to 250 kg/m² receive a bonus of 2 dB. New component measurements even show further improvements. With walls and solid roofs made of aerated concrete, all exterior noise level ranges can be acoustically covered.

Hollow brick

The brick has been widespread as a natural building material for thousands of years. Due to its capillary structure, the brick is a natural moisture regulator. It can absorb, store, and rapidly release indoor moisture under favorable outdoor air conditions. Thermal insulation by brick prevents rooms from cooling down too quickly during interrupted heating operation. During the hot season, the brick stores the heat accumulating in the rooms due to its heat storage mass.

Thermal insulation:

The heat absorbed by the massive brick walls, which is taken from the room, is only released back into the room when it is cooler outside and thus the excess heat can be discharged through natural ventilation. This ability of the brick for phase shift and amplitude damping of temperature has been used in southern countries for ages by building massive brick houses (without additional air conditioning).

Heat protection:

Depending on density and lR value, the brick has very good thermal insulation capacity. For example, with lightweight bricks with densities of 0.8 kg/dm³ or 0.9 kg/dm³ and lightweight mortar LM 36, k-values below 0.40 W/m²K can easily be achieved with a common wall thickness of 36.5 cm.

Thermal conductivity:

Walls made of hollow bricks without filling have a higher thermal conductivity in the vertical direction, especially if they were built with conventional thin-bed mortar that does not reliably seal the holes (convection!).

Diffusion resistance:

Monolithic brick masonry made of thermally insulating hollow bricks can achieve thermal conductivity values of about 0.14 W/mK and, with a thickness of 36.5 cm and plaster on both sides, a heat transfer coefficient (k-value) of about 0.35 W/m2K. This value requires the use of lightweight mortars LM 21 and unmortared but interlocked head joints. This results in a strict three-part division of the component cross-section into brick, air-filled head joint, and bed joint made of mortar. Each of these areas individually shows somewhat different moisture protection behavior. For example, the theoretical water vapor diffusion resistance factor of the air-filled joint should be set at µ = 1, while the bed joint should be assumed to be µ = 15 to 35 for lightweight and normal mortar. Various studies have shown that the influence of the bed joints and especially the unmortared head joint on the vapor transport of the entire component is not detectable [2]. This also applies to head joints that are open up to 1 cm. Compared to, for example, wax-sealed joint areas, an average diffusion resistance factor of µ = 8.8 was recorded in the test versus 7.3 for the case of a 1 cm air-filled joint. Thus, for monolithic, highly thermally insulating masonry, uniform and completely uncritical diffusion behavior can be assumed. Furthermore, in these single-layer, plastered constructions, due to the linear temperature behavior and the resulting linear partial vapor pressure profile inside the structure, condensation can never occur.

Sound insulation:

Already 30 cm or 36.5 cm thick single-layer exterior walls made of lightweight bricks, built with lightweight mortar and plastered on both sides, generally meet the requirements of DIN 4109 "Protection against Exterior Noise."

The sound insulation requirements for partition walls set in DIN 4109 are easily met with walls made of bricks with densities up to 2.4 kg/dm³.
According to suitability test III for DIN 4109, two-shell party walls made of aerated concrete with 17.5 cm PP4-0.6 and 50 m

Calcium silicate stone

Calcium silicate stone consists of a mixture containing lime, sand, and water, which is pressed and cured without chemical additives. The hardening temperature in the environmentally friendly stone production process is 160 - 200 °C. This relatively low temperature for steam curing results in low energy consumption during production. No pollutants are generated. For this reason, calcium silicate stones make a significant contribution to energy saving and thus to ecological balance.

Thermal insulation:

The thermal insulating properties are poor. Depending on density, the thermal conductivity ranges between 0.5 and 1.3 W/mK.

Heat storage:

Due to the high thermal conductivity in exterior walls, additional insulation is indispensable to meet the requirements of the Energy Saving Ordinance. Highly insulated exterior wall constructions comply with the demands of building ecology.

Sound insulation:

Calcium silicate stones have a very high density and are therefore very heavy. Consequently, they have very good properties with regard to sound insulation. Since they are also very compressive-resistant, thin, highly load-bearing walls with very good sound insulation can be constructed with calcium silicate stones.
In the shell spacing, fully filled with mineral insulation material, even the requirements for enhanced sound insulation are met.

.... there are people who do not choose the possible aerated concrete because of the aluminum

What does that mean?


**Source: my website

Rhenish greetings

If you are very environmentally conscious, you will meet people who are "afraid" of aluminum - whether in water bottles or in deodorant, as it is suspected to promote Alzheimer’s (not confirmed or proven) - therefore they also reject the aerated concrete blocks, which get their pores through firing of aluminum. There are also people who dislike reinforcement because it affects the radiation field, etc...

Thank you, building expert! The excursus was worth it. I didn't know much about KS yet.

: Is this your first offer or have you already obtained several offers on the “market”?