New single-family house (KFW70)/aerated concrete vs. sand-lime brick/what to use?

Use Poroton, even better values from aerated concrete, but more complicated to work with because all joints must be installed 100% airtight, especially the seams. Otherwise, you will have nice drafts in the chambers, which can cause bad drafts at sockets or drilled baseboards.

Hello everyone,

as already mentioned in the thread, we are building a KFW70 single-family house in solid construction with sand-lime brick without a basement.

The wall structure is as follows:
- Sand-lime brick 15cm
- Mineral fiber WLG35 16cm
- Air layer
- Clinker brick 11.5cm

(Interior walls 11.5cm sand-lime brick)

As a layperson, I had assumed that an ISO base block would be laid on the floor slab.
However, the general contractor is installing an aerated concrete block (PPW 6-0.65) on a bitumen welding membrane, then continuing with sand-lime bricks.

Is this okay from your point of view? Or does it not really fit together?

Thanks already for your comments/tips,
Lacos

....However, the GU installs an aerated concrete block (PPW 6-0.65) here on a bitumen torch-on membrane, then continues with sand-lime bricks...

Why does he do that? It is always cheaper to stay within the "system" (E-module). At the "foot" of a load-bearing wall, the entire load transfer from the masonry above takes place. The compressive strength should be equal to or higher than that of the masonry above. I would not want lower values.

Best regards

Why this was done that way I cannot say exactly. The first statement was the advantage of better insulating properties.

..... First statement was the advantage of better insulation properties.

I simply lack the time to adequately comment on every statement. But the argument is largely pointless. The essential insulation effect in your wall structure as a whole comes from the additional insulation, not from the load-bearing shell! Here KfW is intended or applied for. Usually, the WB are generally considered according to 4108 Bbl.2 with 0.05 W/m²K. That means that all WB must exactly correspond to the norm 1:1. If there are deviations from this, proof of equivalence is required! Whether this possibly plays a role here is unknown to me.

Best regards

The load-bearing walls of my house are made of sand-lime brick (20cm or 25cm in the basement). Then there is a 14cm mineral wool insulation and the clinker bricks I have selected.

I think that should be fine. There are pros and cons with every material, after all.