ᐅ Single-Family Home: Which Type of Masonry Is Right for Us?

Hello everyone,

We are currently planning our own home and are quite overwhelmed by the many controversial opinions regarding walls and construction techniques.

Our current ideas:

• Urban villa, or if the zoning plan does not allow it, possibly a mansard roof; in any case, two full stories.
• Should be KfW 55 standard, hoping to get better financing through additional subsidies (no equity available apart from the land purchase costs)
• The lower half should be brick-faced
• Mechanical ventilation with heat recovery for better indoor climate and comfort
• We do not want prefabricated timber houses.
• I have ruled out aerated concrete blocks (Ytong) because we are not skilled in craftsmanship, and I worry about leaving large damage when attempting installations.

Now, the question for us is the construction method.

As far as I understand, the three options remaining for us are:

• Poroton (clay blocks)
• Pros
• Drilling is straightforward, possibly special anchors needed?
• Cons
• Sound insulation is poor compared to the others
• Brick facing involves high additional costs since usually only fine plaster is applied
• Sand-lime bricks (Calcium silicate blocks)
• Pros
• Drilling is straightforward
• Good sound insulation
• Brick facing relatively inexpensive since a separate façade is needed anyway
• Cons
• Problems with algae growth on the exterior insulation system (ETICS/WDVS)
• Lightweight expanded clay aggregate (LECA) / Liapor (possibly prefabricated walls)
• I have found only a few usable sources on this, but from what I have read so far, it could be an alternative?

Are my statements accurate so far?
Have I overlooked any essential aspects in my considerations?
How should claims like “sand-lime bricks offer better sound insulation” be evaluated?
Is this only relevant in noisy locations (airports, busy roads, etc.), or should it be given more thought generally?
To what extent are properties like sound insulation more important when planning with mechanical ventilation with heat recovery?
Are my concerns about algae growth on external insulation systems outdated? Are there new variants that no longer have this problem?
Lightweight expanded clay / Liapor seems very interesting at first glance based on marketing promises, yet I have the feeling I might be missing something important.

I would be very grateful for your suggestions.