ᐅ Sand-lime brick versus pumice for masonry?

Hello everyone,

Our architects and the structural engineer have specified calcium silicate blocks for the exterior and load-bearing interior walls.

Now we have received a shell construction quote using pumice blocks (according to structural requirements).

Therefore, I would like to discuss the topic of calcium silicate blocks versus pumice blocks with you. What are the advantages and disadvantages of each type of block from your point of view? Who has experience?

Just to clarify: an external thermal insulation composite system (ETICS) will be applied to the masonry.

Thank you very much!

Sand-lime brick looked great as a 2DF facing masonry. But the jumbo formats are not really appealing, and with ETICS (external thermal insulation composite systems), the structural brick becomes less relevant. You already know my mantra: use what the installer is most comfortable working with. I have lived in pumice concrete for a long time, without ETICS, and unfortunately it retains heat very well. The neighbor can’t hear my snoring.

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I’ll follow along. I find the topic interesting as well.

If pumice is something like Ytong but volcanic, then it should be energetically efficient.

Where are you building— in a quiet area or next to a country road?

Briefly summarized.

Calcium silicate brick (sand-lime brick) is one of the best building materials for sound insulation. It has a very high density but has the drawback that it requires external thermal insulation composite systems (ETICS) to be energy efficient.

Lightweight concrete, also known as aerated concrete, Ytong, or autoclaved aerated concrete (AAC), has disadvantages when it comes to sound insulation; even screwing into the wall can cause problems. Of course, there are special anchors for this, but it can still be annoying. On the other hand, it does not require ETICS.

Personally, I would prefer calcium silicate brick since I am a bit sensitive to noise and work shifts.

Others say to use whatever your shell contractor can work with best, but I would not hire a shell contractor who builds with aerated concrete.

How does it compare in terms of cost?

Is the offer with pumice actually monolithic, or is it a combination of pumice and external thermal insulation composite system (ETICS) / exterior insulation and finish system (EIFS)?
Only then can the price difference be properly assessed.

Personally, I prefer sand-lime brick. Mass, stability, sound insulation, price. You can easily build the whole house from one type of masonry unit.

But I don't have any reservations about ETICS / EIFS either.