Expanded clay: advantages and disadvantages, thickness, suppliers

phew… only 4 minutes left to edit… wanted to say. We have already built the second house with KLB bricks and are satisfied. This time the interior walls are made of sand-lime bricks.. the builder recommended it because of sound insulation. Man, that's some hard stuff.. you can't get a nail in… that makes attaching baseboards a torture..

Back then, the expanded clay blocks must have been quite "bumpy." A lot of leveling was probably necessary, and that was simply tedious... That's what a builder friend said. As far as I know, the blocks are now ground flat, which makes things much easier for the masons. We built with KLB blocks.

Phew... only 4 minutes left to edit... wanted to add. We have already built the second house with KLB blocks and are satisfied. This time, the interior walls are made of sand-lime brick... the builder recommended it because of sound insulation. Man, that stuff is tough... you can't get a nail in... which makes attaching baseboards a torture...

Oops, only four minutes left?
KLB uses expanded clay, Meurin too, they have long been available as flat blocks. I have (in a multi-family house) had no problems with expanded clay for all walls. Sand-lime brick is, however, my first choice if someone absolutely wants ETICS and then, so to speak, the structural masonry shell made of load-bearing interior walls; pore bricks are not really my thing (although they are not nearly as crumbly as some builders' tales suggest).

Sand-lime brick in a multi-family house is also the most sensible choice, especially when it comes to sound insulation. You can't hear anything from the neighbors, and even on the ground floor, the front door or the hallway is not audible from the other apartments. For this reason, sand-lime brick would also be suitable for a semi-detached house.

That was also the recommendation from the GU,
Exterior walls [Blähton] and interior walls [KS], plus good doors

Another statement from our main contractor was that he has not seen mold in a [Blähton] house, whether with or without [Kontrollierte-Wohnraumlüftung]. For our two houses, we can confirm this (without [Kontrollierte-Wohnraumlüftung]).

Sand-lime brick in a multi-family house is also the most sensible option when it comes to soundproofing. You don't hear anything from the neighbors, and even in the ground floor the entrance door or the hallway cannot be heard from the other apartments. That is why sand-lime brick would also be suitable for a semi-detached house.

I would also have no concerns about pumice or expanded clay in a semi-detached house (for all walls, exterior, interior, and even the "shared" one), but with porous bricks I would still choose sand-lime brick for the "party wall" there.