Why does my aerated concrete house with 40 cm thick walls still have to be insulated?

In most western and southern regions of the country, aerated concrete walls with a thickness of 400 mm and a density of D400-500 are sufficient. Such a house is based on heat engineering calculations in that climate. But not in Siberian conditions. Of course, with winters like in the last 10 years, the picture is different from the data in the reference books.

Stumbled upon a good site with various online calculators. Among them there is also a heat engineering one. Link: https://www.project-house.by/termocalculator

So what do the heat engineering calculations say? He entered his data on the thickness and density of the wall blocks. Here's what happened:

This thickness is clearly not enough for the climatic conditions of Krasnoyarsk. Or the D500 block density is too high. The difference in thermal resistance with standard values ​​is almost 1 (m2 * gr. C) / W. It would not help even if I built according to the scheme: blocks 200 mm wide and 300 mm in parallel (with alternation) - a wall 500 mm wide.

According to the heat engineering calculation, only less dense blocks (D400 and B2.0) with a wall thickness of 500 mm passed:

Not to say that all this is a discovery for me, a surprise, and it was necessary to take into account this heat engineering calculation at the design stage. Warming will be in any case. But for me, when choosing a wall material, it is also important not to drown the street (as in the case with brick walls), but also to operate the house without insulation in the winter with adequate costs. Insulation minimizes costs.

Go ahead. Does the brick cladding with a 2 cm ventilation gap comply with the norms of heat engineering calculation?

As you can see, no. Not enough to the standard value of 0.38 (m2 * gr. C) / W.

Calculation with facade insulation with a min-slab density of 175 kg / m3:

10 cm of such a mini-slab with a wet facade system (plastered) is sufficient by calculation with a large margin. Of course, I want to know the amount in rubles in comparison, translate the indicators before insulation and after in value terms. Experts write that with 100 mm of insulation on the facade of a panel house, excess heat loss is reduced by almost 3.5 times. Let me emphasize that they are above the norm!

There is a slab for the wet facade system with a density of 135 kg / m3. With it, the resistance to heat transfer grows to 5 (m2 * gr. C) / W. Insulation and stucco facade is a significant cost item. The cost of insulation for a facade made of basalt slabs:

It is estimated that 190 m2 of insulation is required. A ledge was made on the foundation for insulation (insulated slabs of the permanent formwork of the foundation), a ledge of 10-12 cm:

The walls rest on the concrete part of the foundation. And 10 cm of insulation with plaster will level the vertical of the foundation and walls.

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Self-builder blog (c). Photos by the author

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