ᐅ Building a Basement from Aerated Concrete Blocks?

Hello everyone,

We are planning to build a house with a basement, and our plot is ideal for that. We have chosen a company that specializes in solid construction. While reading the building and service specifications, I noticed that the basement is to be built with aerated concrete blocks (PPW) with a wall thickness of 36.5 cm (14 inches). Since my entire family has experience building houses, I asked for their advice, and they all unanimously said they would not build a basement using aerated concrete. Now my question is: Does anyone have experience with this, and what are your opinions regarding aerated concrete for basements?

Hello,

claudi85 schrieb:
Since my whole family has built houses, I asked for their advice, and they all consistently said they would not build a basement from aerated concrete..

What reasons did your family give for that?

Kind regards

My family said that aerated concrete absorbs water quickly and in large amounts. They mentioned that if the exterior walls are sealed against moisture but there is even a tiny leak, aerated concrete will absorb water rapidly and it won’t really dry out again. Another construction company, which builds with bricks, told me that it could be a disadvantage to build a house with aerated concrete, especially if there is a lot of rain during the construction period, as the aerated concrete blocks (Ytong) would soak up a lot of water.

Hello,

claudi85 schrieb:
... Another house building company that works with bricks told me that building a house with aerated concrete might be disadvantageous, especially if there is a lot of rain during the construction period, as Ytong would absorb a lot of water...

Capillarity, on the one hand, determines how quickly and how much water a building component absorbs when it comes into direct contact with moisture (rain, splash water in kitchens and bathrooms, ground moisture, condensation); on the other hand, it influences the drying speed of new or renovated building parts or walls where water vapor transported by diffusion condenses into liquid water. A useful measure for the capillarity of building materials is the water absorption coefficient (w). The water absorption coefficient indicates how much water a material absorbs within a specific time. It shows the amount of water, measured in kilograms, that penetrates one square meter of the wetted surface area of completely dry material within a given time – for example, one second or one hour. Many building materials with a low water absorption coefficient, meaning only slight capillarity, are characterized by a particularly high total "water uptake."**

The capillarity of calcium silicate bricks, pumice concrete, or aerated concrete (also called cellular concrete) is rather weak. Therefore, it takes much longer for them to absorb the same amount of water compared to, for example, bricks. Or provocatively put: aerated concrete is not sold as Seramis®.

**Source: Eichler, Friedrich; Arndt, Horst; Technical Thermal and Moisture Protection in Building 1989; Bauverlag Kur, Friedrich; Indoor Pollutants, Handbook for Healthy Building and Furnishing, 3rd edition, Eichborn Publishing, 1993, p. 545

All building materials have advantages and disadvantages

Kind regards

Personally, I would first wait for or have a soil survey carried out and then make a decision about how to build the basement based on the results of that survey — regardless of all those who claim to be experts in housebuilding just because they have built a house themselves or at least know someone who has.

That is likely to be much more informative, and if you then share the results here, people will be able to give you sound advice. Sorry, I don’t have a crystal ball or the ability to read one.